104 Results for "stebus"

Construction
Log from STEbus 65C02
My initial placement. I have the 32K RAM chips under the ROM sockets. This simplifies wiring a lot. They are directly soldered to the PCB, because they won't be changed and they are nowadays cheap enough to not bother recovering.On the right is...

PAL chips read
Log from STEbus 80C188
2019-02-22 JEDEC files for the two PAL chips arrived, thanks to Andy! 2019-02-23 JED files decompiled. A bit worried the pinout might differ from the manual I have (for a later version hardware). Partly a red herring, the decompiler produces expressions...

STEbus I/O prototyping board
Details from STEbus I/O prototyping board
The circuit shows how simple it is. Technology has progressed so much that one can easily fit a megabyte of RAM on a processor board for less than the cost of a DIN41612 connector. Graphics cards are memory mapped, but these days most people have a PC...

Project proposal
Log from STEbus Z8000
I propose starting from an existing CP/M-8000 machine project, which looks like this: My project proposal is to construct on a Eurocard (160x100 mm)replace multiple TTL chips with GAL chipsadd a FIFO-interface USB module (replacing the Z8530 UART...

STEbus 8255 Parallel I/O
Details from STEbus 8255 Parallel I/O
At first sight, parallel digital I/O seems simple and straightforward. You make a board with 40 lines of I/O and cable it to a 40-channel signal conditioning board. Some people needed more, and that doubles the boards and cabling. One can try making...

STEbus backplane
Details from STEbus backplane
Any fool can invent a bus, and many have. It isn't as simple as most people think, because as wires get longer they start behaving like transmission lines. Signals take time to travel, and bounce back from the end of wires. Wires act like antennae,...

ISA bus slave NS32016 processor board
Details from ISA bus slave NS32016 processor board
The PD32, was published in Micro Cornucopia number 32, (October/November 1986), page 6. Supports the 32016. Has 512k bytes of DRAM modules. It is a complete processor board. It has no bus interface. It communicates through an 8-bit bus, but not...

STEbus Z80 and BASIC compiler
Details from STEbus Z80 and BASIC compiler
The photo shows the board fitted with two 8K RAM chips for a grand total of 16K.I've replaced them with a 32K RAM and a 64K ROM. This required modding the PAL equations, and wiring extra address lines Another issue is that the ROM is mapped from 0000...

Project Log
Log from STEbus 68B09E
2019-05-30 I'd been putting this project off for a while because it is very complicated to get fully working and I have no known-good firmware specifically for it. I considered porting a monitor but a BASIC interpreter would be more impressive. Grant...

PCB layout
Log from STEbus backplane
The connector side is almost entirely covered with copper, which is the ground plane for all bus signals. This is essential, because it ensures every signal has identical controlled impedance. The STEbus specification states: 7.6.2 Characteristic Impedance...

Altera Quartus
Log from Skills set
In 2001 I chose to go with Xilinx chips and design tools, because they are based on the same ordinary silicon technology used to make RAM chips and microprocessors. Infinitely reprogrammable and presumably cheaper than non-volatile technology. I learnt...

Project journal
Log from STEbus Z180 slave board (SP180)
2024-01-20 I've just found and bought this board from eBay. Made by DSP Design Ltd. It uses the 7-thou pitch DIL packaged device (ugh!) which can only access half the memory of the PLCC68 version. I don't expect this to come with a manual or circuit...

The SGT1
Log from STEbus 6845/6803 video board
The SGT1 was an STEbus colour graphics video board based on the 6845 with a 6803 microcontroller and 64K of DRAM. The 6803 drew text characters on the pixel graphics display. It was quickly superseded by more advanced video boards, and the hardware...

False starts are sometimes the best starts....
Log from HB6809 Homebrew computer
So it has been a long time since the last update, but here goes.... So I built up the Grant Searle / Jeff Tranter Single board 6809 computer on a breadboard: If you haven't checked out the minimal 6809 on their sites its a good read both of them,...

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