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eForth for cheap STM8S gadgets

Turn cheap modules from AliExpress into interactive development kits!

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STM8 eForth is a compact interactive Forth programming platform for STM8S and STM8L µCs. Code and binaries support many low-cost modules, e.g. the W1209 thermostat or the C0135 MODBUS relay board, and a layered build system makes it easy to add yours.

The project supports all STM8 devices, provides a library and serial interface options, uses test automation with uCsim and Docker on Travis-CI, and has e4thcom support for interactive programming.

The list of features includes Idle- and Background Tasks, interrupt handlers, I/O redirection, 7S LED or LCD drivers, analog and digital I/O, string evaluation, the VOC dictionary extension, and ALIAS for temporary dictionary entries.

STM8 eForth is based on Dr. C.H. Ting's STM8EF, an STC Forth that compiles machine code. Since the SDCC assembler and linker are used for building the Forth core, embedding it in C applications is possible. e.g. as a scripting engine.

What is it?

STM8 eForth is among the smallest user friendly Forth systems for µCs: it brings the simplicity of a 1980s style Forth to today's low-cost controllers. The project provides code for STM8 variants, board support for selected low cost targets, and docs. STM8 eForth has a long feature list but it uses very little memory. Innovative solutions, steady support, and an active community makes using it for new projects easy!

The code and binaries on GitHub can be used in many ways:

  • as an alternative firmware for Chinese commodity boards (e.g. thermostats, DCDC converters, and relay boards)
  • build embedded systems with an interactive shell (scriptable and extensible)
  • for creating smart sensors with SPI, I2C, or RS232 and a scripting shell, e.g. for RaspberryPi, Arduino, or ESP8266
  • as an interactive environment for exploring the STM8 architecture
  • for learning Forth - it's easy and fun (find out why in the text below!)
  • ...

Why a Forth for Cheap Chinese boards?

Because it's fun: cheap mass-produced imperfection is a playground for creativity :-)

The W1209 has long been my favourite target: it's a rather complete embedded control board with a UI at a very good price. It's as cheap as it looks, and the challenge is in it's imperfections: the guy who designed the board clearly didn't have a connected application in mind, and I had a lot of fun making it do things it was never intended to do.

There are challenges, like the lack of communication ports. The "sensor connector" can either be used as a a 2-wire RS232 "bus" or for sensing. If you need sensing and communication at the same time the project also provides a full-duplex 3-wire RS232 interface through the key pins (while keeping the keys functional). A plug-in system makes it easy to test new ideas, like using the "update connector" as a home brew field bus interface!

Which target boards are supported?

Besides generic targets for STM8S001, STM8S103, STM8S105, STM8S207 and STM8L051, there is currently support for the following boards:

Some more boards can be supported on request, e.g.

@Elliot Williams worked on using the ESP-14 as an IoT deviced (the ESP-14 module combines an ESP8266 with an STM8S003F3P6).

Programmable power supplies based on the XH-M188 and a cheap DC/DC converter are both work in progress. There are also several types of STM8S003F3 based voltmeters that are known to work.

Read more about possible future targets below.

Why Forth?

Again, because it's fun!

Forth starts out as a stack machine with a tiny instruction set and minimal hardware requirements. It fits in a few KiB, and the target, even a lowly µC, can even be used as the development system. The Forth stack machine is a minimalistic VM on a standard CPU, but there are also hardware implementations (e.g. for FPGAs, or a 144 core Forth processor). The VM is ideal for fast context switching and Forth easily meets hard-real-time requirements. It's no surprise that Forth was used in many NASA projects.

Consider this:

  • compared to other programming environments Forth is easy to understand fully
  • like Lisp, Forth has a REPL (Read-Evaluate-Print-Loop) which enables software testing in a way impossible with "Edit-Compile-Run-Debug" (e.g. Arduino)
  • it's easy to build Domain Specific Languages (one can literally program the compiler!)
  • the stack-oriented "factoring" method results in implicit data flow and modular code
  • Interpreter-compiler, basic OS functions fit in just 4K code :-)

A Forth programmer is in control of all levels of problem abstraction, a unique advantage in a...

Read more »

2157_stm8ef.zip

Original version of STM8EFalong with docs as received from Dr. C.H. Ting on 21/Nov/2016. The docs are worth reading, the eForth binary will run on the STM8S Discovery.

Zip Archive - 21.97 kB - 11/21/2016 at 20:13

Download

  • 1 × ST-Link V2 ICP adapter (e.g. $2.00 from AliExpress) The ST-Link on an STM8S Discovery Board can be used, too
  • 1 × serial interface adapter /w 3.3V signal level (e.g. $0.60) e.g a USB interfacea with a CH340, or better a PL2303, chip
  • 1 × STM8S target device as listed in the GitHub Wiki (e.g. a $0.70 "STM8S103F3P6 minimal system board") e.g. "STM8S103F3P6 STM8S development board" from your favorite China source
  • 1 × Some headers, patchwires, breadboard etc (about $2.00) and other things you fancy, e.g. a RC-servo, SPI display, LEDs ...

  • A big fat bug in double/word division... lingering in the code for nearly 10 years!

    Thomas02/09/2021 at 17:31 0 comments

    What happens when a user tells you about a bug in a completely inconspicuous part of a software, one that you never touched and that you'd thought of as reliable since you'd been working with the software? It happened to me last week, and disbelieve was naturally my first reaction but the problem in UM/MOD, the "32/16bit-division-with-remainder" was real!

    The same user quickly found a bug and provided a fix. I then informed the owner of another project, that started off of Dr. Ting's "STM8EF for the STM8S Discovery", also had never noticed any problem although he had identified and fixed another unrelated bug in UM/MOD!

    What started then was a thorough analysis of the code, which unearthed yet another bug related to an edge case. Automated testing with a Python script makes more bugs in that code very unlikely.

    The moral is this: bugs happen, and they can be very well hidden under other layers of code that "rescues" the expected behavior but open source software not only leads to much better testing for unexpected things but it can also make skilled teams appear out of thin air!

  • New e4thcom features (matched by codeload.py)

    Thomas01/24/2021 at 21:48 0 comments

    Manfred Mahlow published version 0.8.5 of the embedded Forth terminal and programming tool e4thcom which introduces the source file level keywords #ifdef <name> and #ifndef <name>: they make e4thcom check if <name> is defined in the target dictionary and transfer the rest of the line on that condition

    The following example shows the source level keywords supported by e4thcom and codeload.py :

    #include hw/pd8544.fs \ unconditional uploading
    #require ALIAS \ conditional uploading if the word ALIAS isn't in the dictionary
    
    \res MCU: STM8S103  \ use the STM8S103.efr symbol/address file
    
    \ get GPIO registers addresses, insert definitions like `hex 5000 CONSTANT PA_ODR`
    \res export PA_ODR PA_IDR PA_DDR PA_CR1 PA_CR2
    
    #ifndef OUT! \res export PB_ODR
    #ifndef OUT! : OUT! ( f -- ) PB_ODR 4 B! ;
    
    \\ ignore the rest
     of the file

    This feature is useful for testing target properties while sending code to the target. Writing device independent low-level code is among possible use cases.

    The codeload.py in the STM8 eForth tools folder, very useful for transferring code to the target from the command line, now also supports this feature. There are some more improvements, e.g. better newline handling, better error messages and support of Python3 by default.

  • Docs for "STM8 eForth Compiler and Assembly" updated

    Thomas12/24/2020 at 08:05 0 comments

    After the recent introduction of >REL for control structures with relative addressing the docs for the STM8 eForth Assembler Interface were in need of an update.

    I used the opportunity to restructure the paragraphs a bit. Feedback is welcome!

  • STM8 eForth Pre-Release 2.2.27.pre1 is out

    Thomas12/22/2020 at 15:42 0 comments

    I just published STM8 eForth 2.2.27.pre1:

    the GitHub release notes list the most important features, e.g. optional relative addressing for IF .. ELSE .. THEN, support for defining the "Background Task" event in user code (e.g. the RTC alarm).

  • STM8 eForth: IR Remote Controll for an RGBW LED Bulb

    Thomas12/20/2020 at 06:04 0 comments

    Today, IR remote control is by far the cheapest option for consumer electronics. I've long had the idea that Forth is ideal for interactive scripting of IR remote-controlled devices, and I used the light bulb at my desk to learn how to do it with STM8 eForth.

    imagePulseView and an IR receiver (a rather dated SHARP GP1UD272XK) revealed that the protocol is a "NEC" variant:https://user-images.githubusercontent.com/5466977/102696284-81963b00-422d-11eb-9332-a2e0eb6aabf7.pngAfter some learning, thinking and coding, entering "7 ir<enter>" is all it takes for switching this $2 miracle on. The solution is quite generic and controlling other devices shouldn't be difficult.

    I made a write-up of what I learned, including surprisingly simple working code in this GitHub Gist.

  • Easy I2C with STM8 eForth

    Thomas12/03/2020 at 21:42 0 comments

    I had some fun experimenting with the STM8 I2C peripheral. Working around its quirks and designing a code efficient yet reliable and easy to use I2C driver was a challenge. In my previous log entry I mentioned improvements for mixing control structures with optimized assembler code in ISRs.

    After testing some alternatives I ended up with a very simple approach:

    • Device initialization and buffer definition in user code in user code
    • An ISR with a simple API
      • variable I2ISR as configuration "registers" for the ISR
      • I2S ( c -- ) start I2C transmission sequence with device address c
      • I2W ( -- ) wait for end of transmission (optional)

    The ISR is now really easy to use. Here is the code for a 24C64 EEPROM:

    \res MCU: STM8S103
    
    \ Initialization code, e.g. for 100kBit
    #require I2I
    
    \ ISR based I2C "Master transmitter/receiver"
    #require I2CMA
    
    \ temporary constants for the I2C user code
    I2ISR 2 + CONSTANT TCOUNT  \ char number of bytes TX
    I2ISR 3 + CONSTANT RCOUNT  \ char number of bytes RX
    I2ISR 4 + CONSTANT TPOINT  \ points to TX buffer, starting with CMD/ADDR
    I2ISR 6 + CONSTANT RPOINT  \ points to RX buffr
    
    80 CONSTANT SA24C64
    
    NVM
    
    VARIABLE EADDR
    VARIABLE BUFFER 6 ALLOT
    
    : write ( a c -- )
      \  BUFFER follows EADDR, c=0 at least writes the address
      ( c ) 2+ TCOUNT C!   \ TCOUNT, # bytes incl. EADDR
      ( a ) EADDR !        \ set EEPROM address
      EADDR TPOINT !       \ initialize transfer pointer
      SA24C64 I2S
    ;
    
    : read ( a c -- )
      BUFFER RPOINT !      \ set read pointer to buffer
      ( c ) RCOUNT C!      \ RCOUNT
      ( a ) 0 write        \ zero-write sets EADDR and starts the read sequence
    ;
    
    RAM
    
    \\ Example
    
    I2I
    $AA55 BUFFER !
    $0011 2 write
    $0011 2 read
    

    The ISR deals with the different even sequences in the reference manual and it also catches errors.

    Using the error event writing a simple I2C scanner is very easy:

    \res MCU: STM8S103
    
    \ Initialization code, e.g. for 100kBit
    #require I2I
    
    \ ISR based I2C "Master transmitter/receiver"
    #require I2ISR
    
    : scan ( -- )
      I2I
      127 FOR 
        I 16 MOD 15 = IF CR THEN 
        I2S I2W  \ send address and wait for ACK/NACK
        I2ISR @ 0< IF ."  --" ELSE I . THEN  
      NEXT
    ;
    
    scan
     -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
     -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
     -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 80
     79 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
     -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
     -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
     -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
     -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- ok

    A negative value in I2ISR indicates that there was a transmission error (the MSB also contains the error event flags). In the listing above shows replies from a DS1621 at A2:0=7 (79) and from a 24C64 EEPROM at A2:0=0 (80).

    I also wrote test code for the DS1621 temperature sensor (which has a 8 bit command instead of the 16 bit address in the case of the EEPROM) which was just a few lines of code. Accessing any 7bit I2C device should be really easy now.

    Edit: @Eelco did some serious testing with the well known SSD1306 128x64 OLED display.  After discussing a slightly more involved API (extra command interface) it was decided to keep the original simple API. Working code for the SSD1306 is in this GitHub Gist comment.

  • IF .. ELSE .. THEN with Relative Addressing - Changing the Compiler during Compilation

    Thomas11/26/2020 at 06:32 0 comments

    When implementing a driver for the STM8 I2C peripheral I needed BTJx and JREQ branches in Forth code. This wasn't the first time I did that and I had prepared some code to calculated and fix the relative address at the target "label". When I also needed an ELSE block it struck me that this had been solved before - in IF ... ELSE ... THEN.

    Here is the code:

    \ STM8eForth : control structures with relative addressing         TG9541-201124
    \ ------------------------------------------------------------------------------
    
    #require >Y
    
    : THEN ( -- ) [COMPILE] [ HERE OVER - 1- SWAP C! [COMPILE] ] ; IMMEDIATE
    
    : >REL ( -- ) HERE 0 C, ;  \ like >MARK for rel. branch
    
    : ELSE ( -- )  [COMPILE] [ $20 C, [COMPILE] ] >REL   \ JRA rel
        SWAP [COMPILE] THEN ; IMMEDIATE
    
    : JREQ ( F:Z -- ) [COMPILE] [ $27 C, [COMPILE] ] >REL ; IMMEDIATE
    
    : IF ( n -- ) COMPILE >Y [COMPILE] JREQ ; IMMEDIATE

    After loading this redefinition of IF .. ELSE .. THEN to RAM, Forth code can be written just like before. When it's no longer needed the temporary compiler change can be discarded and the code using relative addressing remains valid.

    The real difference is that now machine code for branch instructions can be used that work like the library words ]C! or ]B!:

    #require >REL
    
    : ]B@IF ( -- ) 2* $7201 + , , ] >REL ;  \ BTJF  a,#bit,rel
    
    : ]@IF  ( -- ) $90CE , , ( LDW Y,a ) ] [COMPILE] JREQ ;
    
    NVM
    VARIABLE vt
    : testb  [ vt 1 ]B@IF ."  set" ELSE ."  not set" THEN ;
    : testNZ [ vt ]@IF ."  not " THEN ."  zero" ;
    RAM

    The word ]B@IF compiles to "BTJF addr,#bit,rel" and ]@IF compiles to  "LDW Y,#n  JREQ rel".

    I plan to add these words and others like ]C@IF (LD A,addr  JREQ rel) or ]A<IF (CP A,#c JRPL rel) to the library that directly load >REL.

  • STM8L051F3: Experimenting with LSE, BEEP and RTC

    Thomas10/29/2020 at 08:38 0 comments

    I made a write-up about my experiments the STM8L LSE (Low Speed External) oscillator that uses a 32.768kHz crystal to clock peripherals like the RTC.

    For my experiments I used the nrf24stm8l board that I made some time ago but a chip on a standard "green TSSOP20 breakout PCB" for $0.10 with a crystal soldered to pins 1 and 2 also works (caps were not needed when I tried it):


    The write-up gets started with the LSE and the beeper peripheral. Using the beeper is a good test for a crystal oscillator since one can hear the crystal start up! The next experiment introduces the RTC peripheral with a basic example for configuration, initialization and use.

  • A debug console in 4 lines of code

    Thomas10/25/2020 at 08:23 0 comments

    A Forth system on a $0.20 MCU like the STM8S003F3 with 8K ROM and 1K RAM can offer surprising advantages. Based on an idea I found in the ROBOFORTH II tutorial I added of just 4 lines to the latest STM8 eForth release to provide a very simple debug console that allows examining the state of a Forth program in the middle of the execution

    Here is a simple example:

    #require BYE
    : test ( n -- )
      FOR
        I DUP . 2 MOD 0= IF
          CR ."  Break - mind the stack - continue with BYE" CR
          OUTER THEN
      NEXT ."  done"
    ;

    A debug session on a STM8S003F3, where a "FOR ... NEXT" loop is terminated manually by changing the loop counter on the return stack ($3FF growing down), may look like this:

    66 7 test 7 6
     Break - mind the stack - continue with BYE
    $03F0 10 dump
     3F0  23  0  0  A 8D 1E 8D 12  1 1D  0  6 8D 1E 8D 12  1_______________ ok
    bye 5 4      
     Break - mind the stack - continue with BYE
    $03F0 10 dump
     3F0  23  0  0  A 8D 1E 8D 12  1 1D  0  4 8D 1E 8D 12  1_______________ ok
    $3FA ? 4 ok
    0 $3FA ! ok  
    bye done ok
    . 66 ok

    Note that a single misspelled word will clear both the data and the return stacks. This will not only reset the console but it will terminate the program and typing BYE in this situation will crash the system! There is clearly room for improvement in the implementation of the library word BYE here.

    Edit: here is an improved version of BYE, one that will show a more friendly behavior:

    #require OUTER
    : BYE ( -- ) [
      \ exit the interpreter on the condition that OUTER was called
      $1605 ,           \ LDW Y,(5,SP)
      $905A ,           \ DECW Y
      $905A ,           \ DECW Y
      $90FE ,           \ LDW  Y,(Y)
      $90A3 , ' OUTER , \ CPW Y,#OUTER
      $2604 ,           \ JRNE +4
      $9085 ,           \ POPW Y
      $9085 ,           \ POPW Y
      ]
    ;

  • STM8 eForth 2.2.26: The STM8L Release

    Thomas10/24/2020 at 09:26 0 comments

    I released STM8 eForth 2.2.26 that adds support for all STM8S "Mainstream" and STM8L "Low Power" devices, at least that's what I assume.

    No, I didn't test all the 40 STM8S variants, 37 STM8L variants and none of the 47 STM8AF or STM8AL variants listed here. Instead I looked for evidence what's really the difference between all those devices and thus identified two-and-a-half families (STM8S, STM8L and RM0013-STM8L) with "Low", "Medium" and "High density" devices - and that amounts to just 7 STM8 configurations. The rest is specs and marketing "Product Lines". 

    Read more about this in the STM8 eForth 2.2.26 Release Notes!

View all 167 project logs

  • 1
    Step 1

    Get some cheap hardware (e.g. a STM8S103F3P6 breakout board for $0.65 and a ST-Link V2 dongle for $2). download the binary release, flash it, and have fun!

    If you like it, and you want to hack board support code for your favorite STM8China gadget, you need:

  • 2
    Step 2

    a Linux SDCC tool chain installation (installation instructions for SDCC & stm8flash are in the Wiki)

  • 3
    Step 3

    Clone the project on GitHub

View all 4 instructions

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Discussions

jeff1937 wrote 07/29/2017 at 07:38 point

Just wondering does anyone know if it could it be possible to read the temperature of a W1209 via wire serial communication ?

In other words I just want to log the temperature to a computer, but still leave the W1209 to function as a thermostat.

  Are you sure? yes | no

Thomas wrote 08/05/2017 at 13:08 point

Yes, that's possible. The steps are as follows:

1. determine the R_ntc to voltage function (e.g. using a trimmer and an unmodified W1209, 5 values, e.g. 0 deg C, 80 deg C, and 3 values around (and including) the temperature you care most about)

2. flash W1209-FD from the v2.2.13 release

3. determine the ADC6 values for relevant R_ntc from 1.

4. create an interpolation function from 3.

5. write a simple background task that does thermostat control by reading ADC6 and using 4.

6. read the temperature value from 5. using console commands from your computer. Alternatively send the values in the background task

If you describe your use case more precisely, I can write something to get you started


  Are you sure? yes | no

jeff1937 wrote 08/06/2017 at 00:47 point

Thanks Thomas for the helpful reply.

My applications are to turn off a immersion heating element in a cooking pot when the water reaches near to boiling and secondly to operate a fan in a solar dryer at a temperature around 100C, with computer logging every 10 minutes or so.

Thanks for your kind offer of assistance, but I will try to get some unmodified W1209s operating in a circuit, just to get started first.

If I was able to reflash them, I would hope to retain the 3 digit temperature display.  Which sounds easy as you say they are fully supported by STM8EF vectored I/O.

I guess the key pins don't operate when they are used for serial connection, which is OK because the temperature points could be hard coded in software.

  Are you sure? yes | no

Thomas wrote 08/06/2017 at 05:07 point

Jeff1937, thanks for the info! How do you think about making a small project out of this? I've got a feeling that quite some people would be interested in using this :-)

Know what, I've got a couple of spare W1209 boards here. I'll start a new project, and invite you as a team member. Does this sound good?

  Are you sure? yes | no

jeff1937 wrote 08/06/2017 at 06:54 point

Also was thinking that you could use a datasheet for an NTC 10K.

http://eecs.oregonstate.edu/education/docs/datasheets/10kThermistor.pdf

It shows a resistance table between -55 to 125°C.

eg 25°C = 10,000Ω, 80°C = 1,068Ω,  100°C = 549Ω

Then calculate the theoretical voltage at PD6 with a 20k pull-up to 5V.

This would need a later calibration correction adjustment, but should give a good starting point.

  Are you sure? yes | no

jeff1937 wrote 08/06/2017 at 06:59 point

Yes I would like to have a go at making this a project, or helping.

My W1209 boards haven't arrived yet, but there's plenty to learn in the meantime.

  Are you sure? yes | no

Thomas wrote 08/06/2017 at 07:02 point

Good idea, at least to validate the temperature readings we get.

By the way, I started a HaD project for this. Let's continue with our discussion there!

https://hackaday.io/project/26258-w1209-data-logging-thermostat

  Are you sure? yes | no

Thomas wrote 08/06/2017 at 07:16 point

Ok, great! Get's let started. Please visit the project page, and "Follow" the project to get a notification when there is something new.

There is a first project log, where you can add comments. I also added a GitHub project for code and docs.

See you there!

  Are you sure? yes | no

jeff1937 wrote 08/06/2017 at 08:02 point

OK, will follow you there, thanks Thomas

  Are you sure? yes | no

richard wrote 07/22/2017 at 02:02 point

My first attempt at using a W1209 board has been very rewarding. A couple of suggestions for anyone starting out and for the project team:

 

1. I had no success flashing the board with the suggested ST software on http://www.st.com/en/development-tools/st-link-v2.html.  You may also consider the ST software used by the person who published the schematic of the W1209. It can be found at http://www.st.com/en/development-tools/stvp-stm32.html

 

2. When putting the header on for the SWIM connector use 5 pins instead of 4. The 5th pin is a convenient place to tie one end of the diode to for the half duplex link.

 

3. While the SWIMCOM binary may work on the W1209 board, for the newcomer there is a lot of reward in seeing the "4th" string on the LED display once the binary is flashed. With that feedback you know it is just a matter of getting the serial comms to work.

 

4. With the extra pin the SWIM connection would be a much better place to have half duplex communications. It would prevent the serial communication from disrupting measurements on the sensor pin while debugging and gives you a pin that your push on connector holds better.

 

5. Is there a place to share code snippets? For instance, I wanted to blank the display before sending another character to it. I used

 : Clrdisplay \ clear anything showing

        32 E7S 32 E7S 32 E7S ;

 

I also wanted a delay between displaying “On” and “Off”. I used the following but I suspect there is an easier way:

VARIABLE timer

variable bigtimer

 

: tSet TIM 1000 + timer ! ;

: tTest TIM timer @ - 0 < ;

: delayInner tSet begin ttest until ;

: delay 0 bigtimer ! begin delayInner 1 bigtimer +! 25000 bigtimer @ - 0 < until ;

 

If there was a way to share these snippets it may prove useful to the newcomer. Maybe I just don’t understand the features of github well enough *grin*.

 

Anyway, I can recommend this forth implementation to anyone looking to hack one of these boards. I’m having a blast . I only wish I had found about this project before I built my electric gate controller with an atmel avr chip programmed in assembly. I could have just brought a cheap relay board and achieved the same thing without having to fabricate a board, populate it then program it in assembly.

 

Keep up the great work team.

 

Kind regards

Richard

  Are you sure? yes | no

Thomas wrote 07/22/2017 at 08:49 point

Hello Richard, thanks for your comment, it's higly appreciated!
Here are a few pointers to related actions, some new, some in the making.

1: the Wiki is updated https://github.com/TG9541/stm8ef/wiki/STM8S-Programming

2, 3, 4: using a 5-pin header and a diode is a good idea! I'm currently experimenting with using the W1209 key GPIOs (PC4, PC5) for full-duplex communication, which has several advantages. What do you think?

The usability of STM8EF programming is currently under active development.   Especially a. and b. should be helpful for new users:

  a. improved full-duplex serial code, e.g. for W1209 https://github.com/TG9541/stm8ef/issues/41
  b. e4thcom support with libraries
  c. temporay "scaffolding" code in RAM
  d. board hex file generation in uCsim

5: I created a GitHub Gist with your code snippets - let's see if that works as advertised: https://gist.github.com/TG9541/69fa106e88f8ca3a482a79e572c45463 

I created an issue on GitHub https://github.com/TG9541/stm8ef/issues/42
It would be great if you could contribute to  taking the decisions for a better W1209 support. Also feel free to open an issue on GitHub for topic oriented discussion.

Thanks again for your contribution.

  Are you sure? yes | no

richard wrote 07/22/2017 at 10:04 point

Thomas,

great stuff. I've been at it all day so real life drags me away for now. I don't have much to contribute on full or half duplex serial. I used Teraterm and slowed it down (25ms each character, 500ms for each line return) so the compiling could keep up. I was happy with that.

The Github Gist is interesting. Over time it could be really useful. Perhaps the main Github wiki needs to alert readers to it's existence?

I'm happy to help out with the W1209 where I can. You've no doubt heard of the saying "the blind leading the blind". 

The W1209 is a great platform and it is very exciting to think that much of what I used F-PC for years ago I could do on something costing so little. I plan to contribute as much as I can. 

Regards

Richard

  Are you sure? yes | no

Thomas wrote 07/22/2017 at 12:59 point

Richard,

the voice of users is important, especially in a hobby project where there is no such thing as "market research" - users know very well what makes a product  useful for them. One I'd like to figure out is if connecting a serial interface to the keys "+" and "-" is acceptable (the keys will remain usable), at last during interactive programming. The other thing is whether support for "sensor header COM" needs to be maintained, or if I can simply replace it with something better :-)

  Are you sure? yes | no

Thomas wrote 07/22/2017 at 17:06 point

FYI: issue #41 is closed (which means that full duplex communication now works without character delays). I'll make a pre-release.

EDIT: please check the project log

  Are you sure? yes | no

RigTig wrote 02/27/2017 at 21:59 point

Thomas mentioned that a better file loader would be nice. Here is my attempt. Simple to start with, but obviously capable of being expanded with features later. It is in Python2 and runs from the command line of the host machine (mine is LinuxMint).

<code>

#!/usr/bin/env python2

import serial
import sys
import time

port = serial.Serial(
    port='/dev/ttyACM0',
    baudrate=9600,
    parity=serial.PARITY_NONE,
    stopbits=serial.STOPBITS_ONE,    
    bytesize=serial.EIGHTBITS,
    timeout=5)

if len(sys.argv) < 2:
    print('Usage %s ... [fileN]' % (sys.argv[0]))
    sys.exit()

def upload(path):
    with open(path) as source:
        for line in source.readlines():
            time.sleep(0.2)        
            line = line.strip()
            if not line: continue
            if len(line) > 64:
                raise 'Line is too long: %s' % (line)
            print('\n\rsending: ' + line)
            port.write(line)        
            port.write('\n\r')
            chin = ''
            response_buffer = []
            while chin <> '\v':
                response_buffer.append(chin)
                while port.inWaiting() > 0:
                    chin = port.read(1)
            response = ''.join(response_buffer)
            sys.stdout.write(response)

for path in sys.argv[1:]:
    print('Uploading %s' % path)
    upload(path)

</code>

Usage: Save this code as a file (say named loadserial.py) and change its permissions to be executable (just the lines in between the code tags). I put loadserial.py in my local /bin folder. Edit loadserial.py so the port matches what you use when using a terminal console to connect to STM8 machine.

WARNING: I've just noticed that the indentation was inconsistently displayed, and python is indentation sensitive. So be very careful with just copy-and-paste. I'll put a copy of it up on RigTig's Big 3d Printer project here on hackaday.io.

Either put FILE on first line of the file to be sent, or type it into a terminal console and close it, then use a local command line interface thus: <code>  filename file2send </code>. Enjoy!

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Thomas wrote 02/27/2017 at 22:26 point

Hi RigTig, this is cool! Now the last reason not to learn Python (the haploid language, as I use to say) has gone. I'm going to need it in my job, anyway ;-)

PS: I just added the tag v2.2.8.1.snapshot, and this means that the binary size of CORE is below 4096 bytes, complete with the new "transparent" VARIABLE feature

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Thomas wrote 03/04/2017 at 11:07 point

I just tried your loadserial.py script - the handshake seems to work, and compiling code to NVM is very fast compared to the "worst case delay" method!

However, I had to interrupt the script with ctrl-c after the transfer was finished. The reason was that my Forth code ended with "HAND", after which loadserial.py waited in vain for the handshake signal.

I can imagine that an improved uploader does the following:

* handle FILE and HAND (no need to include those in source file), or

* terminate transfer when the response is anything but the handshake character

The next thing on a programmer's wish list is a way for including source files (nested, of course). I can also imagine testing if "base code" has already been transferred, e.g. using some query-response between the Forth system and the uploader.

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Thomas wrote 02/27/2017 at 22:26 point

Hi RigTig, this is cool! Now the last reason not to learn Python (the haploid language, as I use to say) has gone. I'm going to need it in my job, anyway ;-)

PS: I just added the tag v2.2.8.1.snapshot, and this means that the binary size of CORE is below 4096 bytes, complete with the new "transparent" VARIABLE feature

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RigTig wrote 02/23/2017 at 05:44 point

Thanks Thomas for a great environment in which to have lots of fun. I needed VARIABLE to be defined in NVM, but to keep its data in RAM. Some variables need to change for every data line processed (megabytes of GCODE), so using NVM is just not going to cut it for real use. Besides NVM access is slow. So, here is my replacement definition for my project:

: variable create here , 2 $6e +! does> @ ;

Now, this works only in NVM mode, because it makes no sense to use it in RAM mode anyway. Besides the DOES> part would be wiped every COLD or restart. The magic address of $006E is the address of next available RAM when in NVM mode.

If you want to test after a restart or COLD, you need to adjust the address of next available RAM to be after the last used address by a variable. In my case, the last used address was $009e. Note that in RAM  mode, the address of next available RAM is at $006A. So, I typed

$a0 $6a !

and then initialised all variables and they just work. Now this hack is not for every project (obviously), but does show what can be done when a need arises. Enjoy!

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Thomas wrote 02/23/2017 at 21:35 point

Hi RigTig! That's indeed a nice hack, and it is much along the lines of what I had planned.

I'd like to propose the following solution: 

1. some memory below the user dictionary in RAM shall be set aside by adjusting the reset value of USRCP
2. the next variable address for NVM routines shall be stored in the (new) variable USRVAR, which shall be initialized from USRCP
3. when switching from NVM to RAM the reset value of USRCP shall be set to the value of USRVAR

I'd like to check if it's possible to make VARIABLE work transparently in NVM and RAM mode. Most likely writing a different word is easier.

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RigTig wrote 02/24/2017 at 04:09 point

Thanks for compliment. I haven't really tried to make VARIABLE work in both RAM and NVM, but I am sure it'd work. The key is just understanding that there is one level of indirection (address of value instead of value), so RAM variables use an extra 2 bytes over the non-indirect version. Nice to avoid wasting ram, but not really a show-stopper. Coding in assembler should be far more memory efficient than the Forth version, but it's the joy of Forth to be able to do these kinds of things at all (and optimise later when you find that it is really a good idea!).

A hard reset or even COLD needs to preserve the ram space needed by variables, but I prefer not to lock in a pre-determined limit on the number of variables. I also hate wasting valuable resources by committing them for just-in-case scenarios. 

So let's consider the use cases. Is there a need to support programming to NVM, then RAM, and back to NVM? If we say that all NVM variables need to be defined before RAM gets any code, is that reasonable? At least all the ram needed is in one block in this case. Probably a bit hard to communicate to programmers, and practically impossible to enforce.

Even if there is some code compiled into ram before or after NVM variables are created, the only thing needed is to set the ram space used for parsing commands to be above the last used ram for any variable. This happens anyway until COLD or hard reset. Maybe all that is needed is a persistent vector stored in NVM to be used instead of the $0080 for start of ram space for code and variables. Now the incentive is for the programmer not to waste space, so it becomes 'obvious' that defining all NVM variables before using ram for anything else is just better management of the limited ram. VARIABLE needs to update the persistent vector each time, based on current ram pointer. Variables defined in ram waste space after a COLD, but that might just be a price to pay (and is quite ok during interactive development, methinks). Mmm... and RESET needs to reset the vector to first available ram for code and variables back to its compilation default ($0080).

I am sure to have missed something in this ramble, but hey, that's what hacking is about isn't it? If I knew what I was doing, then it is not real hacking! And what other language allows you to play around with how the language itself works, so Go Forth.

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Thomas wrote 02/24/2017 at 06:41 point

RigTig, we're on the same page :-) 

If you read me previous comment carefully you'll find that the "machine" needed for implementing is mainly coded in the difference between "the reset value of USRCP" and "USRCP" (there is one error though: point 2. should be "in the new variable USRVAR which shall be initialized from the reset value of USRCP"). 

One could argue that this means waste of RAM, but actually it's just a buffer for certain use cases. You already mentioned some uses cases, and how much they would "surprise Joe Programmer".

My model for the programming workflow is this:

1. start a session with COLD, reset, or flashing the µC

2. write some test code in RAM (i.e. do the things you'd normally do with the original STM8EF)

3. run COLD and set the stage (e.g. define helper words like here: https://github.com/TG9541/stm8ef/wiki/STM8S-eForth-Programming#low-level-interrupts-in-forth)
4. run NVM, define words, variables etc as you like

5. run RAM, make pointers to the newly defined words, and also to USRVAR persistent

6. return to 4. (write more persistent code) or to 2. (test your code, preferably automated)

Of course, the casual user may miss the finer parts of the "Stage/NVM/RAM/Test/COLD" cycle, but they will notice quickly that words defined in RAM can't be compiled-in (only interpreted) in NVM, and that code compiled in NVM is lost if they forget to run RAM.

As you pointed out, a certain coding style, like defining variables first, isn't difficult to get used to. Setting aside a small buffer (e.g. 32 bytes) as a variable space wouldn't be a big deal, and it would enable the "setting the stage" use case without the risk of immediately overwriting words like IVEC. It's of course also possible to cycle through the steps 2..6 more often (also as a part of the source code) , but a buffer would add some flexibility. In the extreme case (use many variables, use a huge stack), writing test code in RAM would suffer. But hey, when testing words one tests the units, not the whole program where the stack reaches its maximum size.

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Thomas wrote 02/26/2017 at 09:35 point

@RigTig

Please have a look at this: https://github.com/TG9541/stm8ef/tree/variable

The new code has the features discussed above. The behavior of VARIABLE and ALLOT is transparent in NVM mode, and in most cases there is no need to manage RAM allocation. Only if one allocates more than 32 byte RAM in a session it's necessary to cycle through COLD before using variables newly defined in NVM mode.

Edit: preliminary documentation of the new feature is here: https://github.com/TG9541/stm8ef/issues/16#issuecomment-282547170

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RigTig wrote 02/27/2017 at 01:08 point

Thomas, I have to say that your approach is just brilliant. I love the idea of being able to just get more variable space if needed, and not wasting any ram either. 

P.S. We might be both on the same page, but I'm only partway down. I am still getting my head around the STM8EF code. I keep going back and changing the options for a new flash image and it is installed in a second or two. What fun to play with!

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Thomas wrote 02/27/2017 at 07:17 point

@RigTig: thanks for your support! I just pushed a "size reduced" revision to the variable branch. Since I had to do some shuffling, some "review" and "testing" by "an independent person" would be great (in a hobby project that's what's known as "playing with the code" :-)

Currently some RAM gets wasted, but that could be bettered by giving the programmer control over the headroom for RAM allocation (which would be easy).

By the way, I ordered two of the radio modules you've been working on.

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Elliot Williams wrote 01/23/2017 at 08:55 point

Hiya Thomas,

Got an ESP-14-powered device up and running and installed in our basement.  Long story, must write up.

Have you played around with power saving modes on the STM8?  I'm trying to get the part into the AWU / active-halt mode.  

For one, I need the assembler's HALT command, which I've been doing in the worst brute-force means possible: HERE $8e81 , EXECUTE.  (That's HALT and RET in machine code.)  

It halts, at least.  :)  

Coming back out of halt is messy -- it looks like the clocks aren't returned to their original states and so on. I'm probably going to need to implement some start-up code.  Heck, for my purposes, hooking into COLD for a complete reset will work too... That's what I'll try next.

Just wondering if you've worked on any of the low-power modes.  Either WFI (wait-for-interrupt) or the active-halt/AWU look tasty.

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Thomas wrote 01/23/2017 at 19:14 point

That's great :-)

The power saving modes (like the watchdog) still are on my "important things that I plan to do" list. You know, that's the list on the sheet after "new and exciting things I want to play with", which in turn comes after "bugs I must fix now".

Let's put it on the "important new features for pilot applications" list :-) 

What we need is:

* a word HALT that contains the HALT instructionknow

* a word SLEEP, that stops unnecessary interrupts (user defined, and application specific). This word should run HALT. When the execution continues right after HALT, SLEEP shall re-enable "waking" interrupts

* if required a word to restore clock settings (RM0016 mentions something in 10.2.2 and in 9.9.4 "Clock master switch register (CLK_SWR)", but right now I don't undertsand why the clock changes)

Do you plan to trigger a wake-up through console events? The simulated COM port should support this use case!

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Thomas wrote 01/23/2017 at 19:45 point

I added the HALT word, and it works better than expected. Here is a demo with a blinky:

    : g tim 40 and 0= out! ; ok
    ' g bg ! ok
    HALT
The when I press enter after HALT the LED stops flashing. The "ok" after HALT appears after I press enter a second time.

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Elliot Williams wrote 01/24/2017 at 11:52 point

Woot!  

re: clocks: I read something somewhere sometime about them needing a reset.  I can't find that anymore.  I may be crazy.  

I saw some other STM8 code (http://blog.mark-stevens.co.uk/2014/06/auto-wakeup-stm8s/) that runs the AWU without re-clocking, strongly suggesting that I'm crazy.

That code, though, makes it look like (if interrupts are enabled) the AWU reset lands in the AWU ISR, which is uninitialized ($0000) in the vector table at $800C.

I just ran your BG example above, and it halts, but never returns until hit with a hard reset. I wonder if your code is working b/c it NOPs off to the next ISR and you got lucky.  Or does it actually try to execute whatever's at $0000?

So: how do we set up ISRs in eForth?  (Or, how do you write bytes directly to flash?)

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Thomas wrote 01/24/2017 at 19:23 point

TL;DR: the quick-fix: an AWU "driver" that does it all but I would prefer a Forth solution and this requires some design decisions.

Long version:

Due to limitations in the SDCC tool chain any interrupt must be declared in main.c. Writing ISR vectors to Flash might work, but it requires a good approach for registering (and unregistering) interrupts to be viable (I'm thinking of RESET). Also Forth VM context switching would have to be done before executing any Forth code.

Another approach would be a "catchall" interrupt handler for several interrupts that then redirects to Forth code. This has the advantage that the context switch can be handled in a uniform way, but the dispatching won't be very efficient (or again a lookup).

This brings us to the next problem: some interrupt sources require resetting some bit in some peripherals control register. Leaving that to user code is very error prone, and a "catchall" interrupt handler would have to do it for all possible sources or leave it to user code.

What do you feel about of a middle way?
* Interrupt handler declared in main.c
* basic handler code in assembler or c to do a context switch, and to clear the trigger source
* handler code in Forth registered through something like BG

A last point: how many concurrent "Forth code interrupts" can we allow?
* Level0 we have the console
* on Level1 is the BG interrupt
* on Level2 is TIM4 (for COM simulation)

I guess that some stuff like TIM4 shouldn't have to compete with other code (the current code is efficient as it gets). Most likely it's possible to drop the interrupt level in BG code to Level0, and use Level1 for Forth handlers without character-I/O. The latency would still be in the lower µs range.

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Elliot Williams wrote 01/25/2017 at 12:43 point

How does the 'BOOT mechanism work?  If you could do placeholders for the various ISRs like that, the user could write their handler function and store its address in the right place?  That seems very Forthy to me.  <code>: awu-isr stuff ; ' awu-isr ISR_AWU ! </code> or something.  One of these functions / memory locations per IRQ and you'd be done?

On resetting the flags as you leave the ISR: I think that should be user code rather than bloating up the system with it.  Yeah, it's going to hang the system if you do it wrong.  If I could count the number of times I've pressed the reset button...

On context switching in ISRs:  I'm not sure I understand the full details.  Unlike C, there's not necessarily any context to switch?  If the ISR maintains stack balance then there's no need for any context?  Leave whatever's on the stack, and it'll still be there when the interrupt is done?

For me, personally, I'd just be stoked to have a pointer to an address that I could set to execute when the AWU IRQ fires.  The rest, I can handle in code, I hope. :)  (Assuming that the return from interrupt works right.)

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Thomas wrote 01/25/2017 at 20:20 point

'BOOT is simple: it returns the address of the "Parameter" field (like DOVAR). To safe code I used it to get the address of the whole following table of initialization values for USR variables. After switching to "NVM" it's possible to simply overwrite all these values. There is a 2nd copy to restore these values, e.g. to "forget" user vocabulary in Flash memory with RESET.

Yes, the 'BOOT method can be used in for interrupts, too, but that would require one more level of indirection.

About context switching:

my first approach was to re-use the Data Stack, but I quickly learned that X isn't always a valid Data Stack Pointer: it does that at the start and the end of a word, but not always in between ("always" is a very important attribute when writing interrupt code). Before implementing the background task, I tried  to make sure that X always represents a valid stack pointer in all primitive words. However, I failed to get it working until I started using a 2nd Data Stack for the background task (which I didn't like since it appears wasteful). Later on, I applied coding techniques that use X for reducing code size. Of course, it's possible to re-factor the code. It would be interesting to compare other multi-tasking Forth implementations. 

I went in a different direction: In several refactoring rounds I removed the following variables entirely: TEMP, XTEMP, PROD1, PROD2, PROD3, CARRY, and I also made the I/O context leaner.

Now, for code without character I/O only YTEMP must be saved. Otherwise also BASE, PAD, and HLD must be taken into consideration. And, of course, we need a stack. One approach would be to have a floating "stack pad" to work around the "X!=TOS" problem.

I guess it will take some time to implement a full featured solution for Forth interrupt handlers.

A minimal solution might look like this:
* a word IVEC! to set an interrupt vector
* a word SAVEC to save the context
* a word RESTC to restore the context, ends with IRET

The application could then define a word in the following way:  

: handler SAVEC ( some stuff ) RESTC ;

 ' handler 1 IVEC! \ set the AWU interrupt handler

Now that I'm looking at it, this doesn't look too bad.

Edit: I made some corrections, added some details, and added one more option for a solution

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Thomas wrote 01/25/2017 at 22:23 point

I added the solution above for testing to the develop branch. Due to the mentioned limitations it's currently necessary to initialize the interrupt to priority low (0:1) (it shares the data stack with the ticker).

I also changed TIM4 to prio "highest", which might allow to implement all user defined interrupts with priority "high" later on. This would then require 3 data stacks with the sizes normal (console), medium (background task) and small (interrupt handler).

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Thomas wrote 01/26/2017 at 20:48 point

@Elliot Williams:

Here is a starting point for Forth code user interrupts and AWU usage:

  nvm

  : awuint savec awu_csr1 c@ drop restc ;

  ' awuint 1 ivec!

  : initawu 38 awu_apr c! 1 awu_tbr c! 16 awu_csr1 c! ;

  ram

When I run HALT with this code, it returns immediately. Since I didn't find the time to make sense of the AWU configuration, I simply took the AWU timing values from the page you mentioned before.

Please not that this currently only works when I run HALT from the console (I still need a solution for the Data Stack problem). Running HALT from the background task would change the contents of the first element on the stack (which would work if the stack were empty).

A quick fix here is to assume that X represents TOS when HALT is executed (which is the case), and skip initializing the stack. Please note that this only works for HALT, and not in the general case.

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Thomas wrote 01/23/2017 at 21:51 point

Changes are in the develpp branch on GitHub. The 2.2.6.snapshot release contains new binaries :-)

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Youlian Troyanov wrote 01/26/2017 at 04:51 point

please write your long story about esp-14 :)

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Thomas wrote 01/27/2017 at 22:19 point

Elliot, in order to get a simple and practical solution, I now propose the following:

1) In RAM code IVEC! (its only used once for setting an interrupt handler

: IVEC! ( a n - -  ) 2* 2* $800A + ! ;

2) Implement HALT as a user word:

: HALT  ( -- ) [ $8E C, ] ;

3) Implement your interrupt handler using SAVEC and RESTC (make sure not to use more than 8 cells on stack)

This will work for any interrupt. Please make sure to change the interrupt down from highest to high.

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jaromir.sukuba wrote 01/23/2017 at 05:17 point

Another tip for *possible* STM8 target http://www.ebay.com/itm/12V-DC-Multifunktionsrelais-PLC-Cycle-Timer-Timing-Delay-Relay-Switch-Module-/131648915593

I didn't buy this one, haven't seen the schematics, but to me it totally smells like it could have STM8 under the display. Googling for XK-001T-1 didn't bring much info, though.

  Are you sure? yes | no

Thomas wrote 01/23/2017 at 06:18 point

Yes, that's possible. In most cases one won't find any schematics, and also the XH-, XK, M- or B monikers aren't always used the same. There is a small list of modules that are very likely STM8S based in the Details Section of this project (in the section "How can I spot suitable boards?"). If there is any interest, I can publish a list with advertised properties and the "street price".
Edit: here is a link with a picture showing the PCB legend:
https://www.aliexpress.com/store/product/Free-shipping-XK-001T-1-DC12V-Time-relay-board-count-voltage-testing-cycle-time-vehicle-charging/1548016_32656999267.html
Based on the outline of the µC I would expect it's not STM8 but a STC15 based, a µC which I've seen several times on "timer" boards (MCS51-like http://www.stcmcu.com/datasheet/stc/STC-AD-PDF/STC15-English.pdf)

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Elliot Williams wrote 12/13/2016 at 23:13 point

Got my ESP-14 up and running last week, and then got distracted.  :)

Short story: it's just a STM8 chip and an ESP8266, like it says on the package.  The TX/RX lines are internally connected, so I was running your Forth on the STM8 with the ESP8266 powered down, and running all manner of software on the ESP with the STM8 powered down.

Been thinking about how to use both at once. 

a) Jeelink is a nice transparent serial port over ESP8266, which would provide remote wireless development of the Forth system on the STM8.  The idea of telnetting over WiFi into an STM8 is funny enough that I'm definitely going to do this.

b) Since the serial port is the only way in to the ESP8266, and the STM8 has only that one hardware serial port, I suppose that bit-banged serial or I2C/SPI could be used to talk to the console. I don't know how hard/easy this is. But then you'd have an STM8 that could issue AT WiFi commands, for instance, or run routines in NodeMCU, which might be very cool.

c) The other option is to code up the ESP and STM8 to take turns based on control characters: 0xFE toggles the ESP on/off the line, and 0xFF toggles the STM8, for instance.   This requires modifying _both_ firmwares, but would allow for the console, ESP, and STM8 to share the UART lines and talk to each other.

Just brainstorming so far. No real hacking yet. 

The breakout board I made for the module just fit it onto a breadboard, because I didn't really know what to expect from the module. It will probably want a transistor so that the STM8 can turn off the ESP8266 for power-saving when necessary, and will certainly want at least a jumper for flashing the ESP.  

Thanks for the case insensitive addition, and for do loops! This is a fun system to play around with.

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Thomas wrote 12/14/2016 at 19:31 point

Options a) and b) look good to me, especially in combination. How about connecting a PNP transistor for the ESP8266 power supply to PD1/SWIM? Normally one would access the STM8 serial port through ESP-Link, and the ICP interface could be used for direct access to the ESP8266 serial interface by simply pulling down both NRST and PD1/SWIM. Direct serial access to the STM8 could be acchieved by telling it to power the ESP8266 down (this might even work using PD1/SWIM once more, e.g. by using an RC element which can be detected testing its timing).

Option c) would also be possible, but at least one of the devices would have to be able to swap RxD and TxD, and the other devices would need a "tristate" mode on TxD. The Bus approach I took for the W1209 might also work for more than two devices.

A fourth option could be to have a Forth word that issues the initialization AT commands on the STM8, and execute it with 'BOOT.

I hope to find the time for some hardware hacking in the holiday season :-)

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Elliot Williams wrote 12/16/2016 at 21:22 point

"esp-link" not jeelink.  https://github.com/jeelabs/esp-link  Tried it and had a telnet / web-console controllable STM8 running your Forth.  Took like 10 minutes.

Then I spent 3 hours trying to implement something like c) in NodeMCU.

First, I thought I'd set up two TCP connections: one for the ESP to be executed locally, and one to pass through to the STM8.  Didn't work b/c NodeMCU can only do one TCP connection, it seems.

Then I thought I'd use MQTT as the transport mechanism.  But there's some glitch there with MQTT and the UART port not working right.  I'll hack more at it before I give up, but it might be time to move on to MicroPython or ESP Basic for the interactive ESP part.

Anyway, try out the esp-link for the ESP when you get around to it.  It's kinda fun.  It _does_ however leave me wanting a more capable microchip on the remote end.  For another couple bucks, I could get a lot more flash, peripherals, and etc to tether to the ESP.

All of this playing around has helped me refine what's needed in a breakout board for this thing, though.  :)

  Are you sure? yes | no

Thomas wrote 12/16/2016 at 22:35 point

Again great news, and I'm going to test esp-link too. Multiplexing communication through MQTT topics was the first thing that came to my mind. About a year ago I tried working with MQTT and NodeMCU, but I was disappointed with the stability of the platform (though I really liked working with Lua).
I guess that the case for ESP-14 is rather thin: as I mentioned before, it looks more like proof that the ESP8266 wasn't able to meet customer requirements than like the solution the world's been waiting for. But who cares as long as it's fun hacking.
In my opinion, a decent Forth environment on the ESP8266 would be rather attractive: C.H. Ting hacked something recently, but it was just the kernel, not a complete framework with persistent vocabulary (and maybe even with source stored in the Flash memory, and maybe even a JavaScript based IDE served from an embedded web server on the chip).

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Thomas wrote 11/28/2016 at 21:33 point

Hi Elliot, it's great to hear that someone got it running, and that the docs were good for a smooth start. Anyhow, congrats for the "STM8EF Blinky"! Did you try to do that BG style, too? 

I had a look at the CAPS issue (yes, I've been thinking about that for a while ;-) ). There are some potential clashes (e.g. PARSE/parse, NEXT,next, ABORT"/abort") but the lowercase words are the hidden "implementation part", and I don't see that their name is set in stone. I decided to name them after their assembly labels (pars, donxt, and aborq). 

New code with lowercase support is on GitHub (just set CASEINSENSITIVE = 1 in globconf.inc). If you'd like to give it a try without building, please let me know (I can drop a binary into the files section here). If there are no issues I'll make it the default.

The ESP-14 will be one of my next targets. However, I didn't find the time to make a breakout PCBs with power supply for this module. Controlling the ESP8266 supply through the STM8S003F3 would be cool. If someone with good access to PCB prototyping could do that job I'd be more than happy to contribute some ideas about the schematics.

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Elliot Williams wrote 11/29/2016 at 15:57 point

I just got an ESP-14 in the mail from ebay today.  I'll be making a breakout for it sometime in early Dec.  (Right now, I'm churning out HaD articles like mad.)  I'll share when I do.

I still have no idea if it makes any sense to run a (powerful) ESP8266 off of a (much smaller) STM8 chip.  But I'm willing to find out.  :)

I also ordered one of those LED/relay boards. Again, just for fun, but maybe I'll do something with it.

Thanks for thinking about caps.  I'll definitely rebuild and reflash. 

No, I didn't get into the multitasking / backgrounding. I just got the thing up and running, not much more.

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Thomas wrote 11/29/2016 at 19:13 point

The ESP-14 is quite strange. I can only guess that an OEM required a solution from Espressif that meets non-functional constraints (e.g. dependability, power consumption, or periphery set) that could not be met by the ESP8266. I don't think that a lack of skilled programmers was the reason. The power consumption of the STM8S003F3 in "active halt mode" is quite low, and for a data logging sensor node a battery life of a year or more with a 100mAh battery might be feasible.

The W1209 boards are really fun, especially with a background task. When you try using STM8EF with it, please let me know if the docs for the single wire half-duplex solution are sufficient.

About the case-insensitive input: you're welcome (the option has a price tag with "23 bytes" on it :-) )

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RigTig wrote 12/15/2016 at 10:44 point

I've created an adapter for ESP14 (and ESP12) to 22-pin DIL, if you haven't done anything else yet (see new project here called 'ESP-12 and ESP-14 adapter to DIL'). My ESP14s arrived today!

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Elliot Williams wrote 11/28/2016 at 13:54 point

Hiya! Been following along, finally got a few minutes to flash stuff to one of those min-dev boards.  Great fun!  I haven't done anything useful with it yet, but I've gotten the LED blinking, naturally.

One thing that's driving me nuts is the ALL CAPS commands.  Is there an easy way to either a) lower-case them all or b) make it run case insensitively?  Or would that cause namespace clashes? It makes my shift-finger hurt. 

And that's it for now.  I have to say that your directions (combined with some of the links that you list) made it very easy to get up and running with the system.  Thanks!

I'm planning a few Forth columns for HaD, and I'm still collecting chips that have working implementations.  You've added one more to the list. 

Oh, and I've ordered an ESP-14.  We'll see how that goes.  Looks like fun. 

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