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RISC Relay CPU

Scientific calculator with a brain built out of relays.

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This project is about building the fastest relay-cpu in the world.

Once you have a homebuilt CPU (and also before it is ready), everyone will ask: What can it do ? So it is important to have a good application to show what the CPU can do. That will also give some focus for the design.

I took a calculator as application. So the device should have calculator keys and a display. It will be a scientific calculator, using floating point calculations, and capable of logarithms and trigonometric functions.

The aim is a speed of a at most a few seconds for add and multiply, and at most 5 to 10 seconds for the scientific functions.

The design will have solid state memories, but might be prepared to work with a diode-ROM
and/or capacitor-RAM if the application does not need too much memory.

How will the fast speed be accomplished ?

Relays are slow, and to get acceptable performance, many measures must be taken.

Architecture:

  • Microcode will not be used
  • Harvard architecture, so fetch and execute will be in parallel
  • Have enough registers so we're not loading and storing all the time
  • Have a good instruction set
  • Some special instructions tailored to the algorithms that are used

Technology:

  • Design in such a way that for executing an instruction a very low number of consecutive switching relays is needed. At this moment, there are only four consecutive switching relays for an instruction.
  • Use small relays, these can be fast (datasheets show 2 msec switching time). Using small relays means they take less space on a pcb, so not much pcb area will be needed.

The design is shown in the following block diagram (click on it for a larger version):

The block diagram also shows which functions the twelve PCB's and the backplane contain.

Now that all schematics and also all pcb's are designed, I can give a quite accurate listing of the number of main components:

The architecture is explained in the architecture document (see Files section). Highlights are:

  • All instruction, register, word and memory sizes are 16 bit.
  • Most instructions operate in a single cycle.
  • There are eight 16-bit registers, one of them is the PC.
  • Six registers can be paired to form three 32-bit registers (like the H and L registers in the 8080 / Z80 ). Many instructions have a 32-bit variant that operates on register pairs (using 2 cycles but single instruction word).
  • It is a 2-operand design, 1 operand is a register and the other one can be register, memory, or immediate. If the immediate is only 8 bits (7bits + sign), it is included in the 16-bit opcode and the instruction executes in a single cycle.
  • Memory addressing always has a small displacement within the instruction opcode, facilitating addressing of variables in a stack frame, or addressing of structure members. Instructions that use this need only a single cycle.
  • The ALU has also decimal instructions (in addition to the normal binary instructions), to support the calculator functions.
  • There is a special instruction to support (decimal) multiplication.
  • The ALU has special instructions to convert the 4 nibbles in a register to bits that control a 7-segment display.

The architecture is independent from the technology, so it could also be used for a TTL or FPGA design. It can be upgraded to a full 32-bit design. Actually, since there are 32-bit register pairs, it would be easy to support a 32-bit address bus.

Use of the architecture is free for non-commercial use :), but I would like to get a mail when you are going to use it.

Next to the processing boards can be one or more boards to implement the memory.

What has to be done:

  • Have an architecture.
  • Have a schematic.
  • Have a simulation. The 4-bit boards have been low-level simulated in Logisim. I do not have a good logisim model for a relay, so the simulation might not catch all problems. Many instructions have also been simulated.
  • Built an assembler and simulator. Simulating the application before the design is finished gives a chance to optimize the CPU for the application.
  • PCB design 
  • PCB ordering
  • Build an 8-bit version (this does not need all PCBs)
  • Build a programmer for burning the flash memories
  • Have a test strategy, and test.
  • Find the causes of problems, and correct them (now, may 2018)
  • Build the full 16-bit version

Adobe Portable Document Format - 144.88 kB - 05/21/2018 at 17:09

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Risc Relay CPU gerbers 20180505.zip

Gerber PCB design files of all 9 pcb's

x-zip-compressed - 960.40 kB - 05/05/2018 at 20:12

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x-zip-compressed - 849.16 kB - 05/05/2018 at 19:54

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PCB signals 20171014.zip

A collection of spreadsheets with quite accurate description of the signals at the connectors of the pcb's

x-zip-compressed - 76.96 kB - 10/14/2017 at 15:25

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RRC1613.pdf

Schematic that shows essentials of the datapath and instruction decoder.

Adobe Portable Document Format - 45.87 kB - 05/24/2016 at 20:15

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  • Off by one error

    roelh07/04/2018 at 20:47 0 comments

    The Risc Relay CPU is in the Homebuilt CPUs WebRing now !!  Celebrate !!

    In the last weeks I did build most remaining boards and did more testing. All registers are available now, and the second ALU board is ready, so the full 16 bit data handling is in place.

    The new ALU and register cards were first tested with the test device, and the soldering problems that were found were corrected.

    Then everything was put together. (Only the second Program Counter board, and the keyboard are still missing.) This was too much for my 2A benchtop power supply, it showed the LED's slightly dimming during operations. So I changed to a beefy 24V 10A supply.

    This was tested:

    • 32 bit decimal addition, working
    • bit shift unit, working (after fix)
    • load constant from code space, working (but not supported by assembler yet)
    • subroutine call, problem !

    All tests only worked after one or a few soldering issues were fixed. In the shift unit, one of the diodes (D609) was not connected on the schematic, so a short wire was needed. On the boards with 3 registers, 8 short wires were placed (this was planned), to enable register DH to receive input over the LINK bus (return address). The register pcb uses almost all 96 connector pins. Therefore, the link bus was connected to the output of register C (register C is not placed on these pcbs), and on the pcb there are wires from the register C outputs to the relay coils of register DH.

    The subroutine call placed the return address in register DH, fine. But when, in the return instruction (LD PC,DH), the DH register is moved to the PC, the PC is incremented before the next instruction is fetched. That means that the instruction after the call is skipped ! A classic off-by-one error. I have not yet decided what to do about this, there are several possibilities.

  • Good progress

    roelh05/21/2018 at 17:40 0 comments

    A few weeks ago, I connected a Raspberry Pi to the program flash memory of the computer. The Raspberry Pi runs the assembler-simulator in its webbrowser. The assembler-simulator has buttons for upload and download from/to the RPi. The RPi is connected with a 16-bit data connection to the Flash program memory, through a small pcb (containing resistors for level conversion). The PROG pcb, that contains the flash chips, also has two 74HC574 registers to store the address for writing the flash. The RPi has a small Phyton program that burns the generated binary in the two Flash memories of the relay CPU. 

    From that moment on, I could run real programs on the computer, although the cpu is only partially built: The data is only 8 bit wide (in stead of 16). Only 4 8-bit registers are present, and it does not run at full speed. 

    Then came several days of serious debugging. Several problems could be fixed by changing the instruction encoding or changing the simulator:

    • In conditional branches, true and false were swapped
    • After a branch or jump, the first instruction was skipped because the hardware first increments the PC and then fetches an instruction
    • The 7-segment decoder had the two segment groups swapped. So the X register got the segment bits that were intended for the Y register and the other way around. So the single segment instruction was now split in two segment instructions, with the segment group specified in instruction bit 5 (this was an unused bit for zero page addressing). Small hardware change.

    The architecture and instructions document was updated with the encoding changes.

    Several instructions were working unreliable. All these problems were fixed by changing the hold resistor (2K on the schematics) to 1K5.  One non-soldered diode was found.

    Not all instructions are tested yet, but all tested instructions work now. I made a small demo program that calculates Fibonacci numbers.

    This weekend, I gave the RISC Relay CPU its own website: RISC Relay CPU Website. Some things on the website might still be a bit quirky.

    A video of the working computer is on the new website (including sound ;) !

  • First instructions executed

    roelh05/05/2018 at 20:28 0 comments

    Annoying how slow the progress is if you can not spend enough time on your project....

    Just a few days after the last update, I also connected the 8-bit ALU board and the 4x8 bit register board to the motherboard. This should make 8 of the 16 databits and half of the registers operational.

    I could enter instructions manually with the buttons connected with a flatcable to the PROG pcb (described in previous log). And YES, I could execute several instructions successfully, like addition, saving to RAM, loading from RAM !  I did not test all instructions, but I do not remember an instruction go wrong (that may be selective memory, it's already a few months ago).

    Anyway, testing branches can not be fully done in this way. The control system will not load the instruction that follows a branch, so that it executes as NOP. But it has no way to prevent me from entering instructions manually...  So there is no escaping, it is time for a real program to be run from flash memory. 

    So the next sub-project is a flash memory programmer. I intend to do this with a Raspberry Pi. It can connect to my website that provides the javascript assembler. It could simply write the object code to its own filesystem, and then a Python program could program the parallel flash through RPi I/O.

    The javascript SIMAS (simulator-assembler) had an annoying 'feature', it did run quite slow. I examined it, and found that for small programs it was OK but with longer assembly programs it became slow. I suspected the Angular framework code. So I threw that out, I didn't understand it very well anyway. But it did not help.

    Then I switched from Chrome to FireFox, and suddenly the speed problem was gone...  I don't know why. But I'm not interested in investigating it further. There are enough other things to do.

    The SIMAS ( simulator-assembler ) had one of the first versions of the instruction set. So I updated it to the newest instruction set. It has two memory spaces now (program and data). To have initialized data, the assembler simply copies the first few hundred bytes of program space to the data space. This is something that a real program will have to do itself.

    The layout of the program was also changed. The left side of the screen now has a textfield for entering your program. The center has a bigger textfield, that shows the source code together with the assembled machine code. And the nicest feature...  in the center window, all program lines that were executed get a blue background, and the current line after the program halted is red. So the blue background shows you the execution path that the software has taken after the last keypress of the calculator.

    The buttons that simulate the calculator were re-ordered, to be similar to the pcb that I designed for the keyboard a few months ago.

    Finally, I worked on the calculator application. It will now do all functions, except the trigonometry functions. The latest code is now automatically loaded when you load the webpage. You can try it at www.enscope.nl/rrca  Before operating the calculator, first press "Assemble" and then "Run".

    I updated the HAD file section. The architecture and instruction listing are now in a single document. The schematics are updated and are according to the pcb's. Gerbers of the pcb's are also provided.

  • Assembling and testing pcb's

    roelh12/30/2017 at 19:16 2 comments

    Around two weeks ago I ordered all remaining pcb's and a lot of parts. They arrived just in time for some happy soldering in the days after Christmas. Each pcb was (sometimes partially) built and then it's main functions were tested, revealing soldering errors but also a few design errors. This is the state today (click it for bigger version):

    1) clock and control pcb

    2) program counter pcb (6 bits) 

    3) instruction decoder pcb (only it's LED's are visible)

    4) program memory and instruction register pcb

    5) RUN button

    6) STOP button

    The pcb's are connected to the main pcb with DIN41612 connectors.

    I started with the program memory and instruction decoder. (All pcb's in this project were intended to have a white color, but apparently I forgot to select the color when I uploaded the gerbers of this pcb). The flash memory itself is not yet assembled. There is a connector (where the ribbon cable connects) that is intended to connect to a flash memory programmer. It is now connected to 16 pushbuttons, to control the contents of the instruction register manually. The instruction register worked (but several of the 2K2 resistors in the hold circuits had to be lowered in value, apparently the current was not enough to keep the relays attracted).

    Next was the clock and control pcb. The clock circuit did not work as expected and had to be modified. Two 100uF elco's (visible on top of the pcb) set the clock to approx. 5 instructions per second, slow enough to have a sense of what is going on during testing. Asymmetry in the clock signal will have to be solved (and higher speed will be set at a later time). One of the board's input signals was not connected, a wire was needed to correct this. Another problem: The single-step button should start executing one instruction and then stop. Unfortunately, the stop function works too well, so much that pressing the single step a second time does not run a next instruction... 

    The program counter pcb also has decoders for reading and writing to the registers. Only the program counter section was mounted for now. After re-soldering a resistor, I started the clock and watched the PC counting...  0, 1, 2, 4, 8, 16 ....  Oh what's wrong ?  Did I build a shift register instead of a counter ?  After following the signals on several wires, it occurred to me. The PC has a master and a slave section, they each have a CLR signal. If one of the registers is not cleared, the bits stay 1 and you get this behaviour.  This is not visible on the LED's if the leds are connected to the slave section and the non-cleared part is the master section. Well, the CLR of the master could be interrupted by relay RL341, and that was not placed because it was considered part of the decoder section. After placing RL341, it was happy counting !

    Now the instruction decoder. It has led's that show the addressing mode ( Memory, Zero page, Immediate, register, test-and-branch) and the instruction ( LD, ADD, AND, OR, XOR ) and a few other output signals. This was simply tested by letting the clock run and manually put something in the instruction register. Many instructions could be tested this way. It revealed an error in the decoding for the DMPY instruction, were inputs to a diode gate had to be connected to IR_Y0 instead of IR_Y0_N. This diode gate was on the pcb with the instruction register, leading to a small modification there. For a LD instruction, also the OR led was on, could be corrected with an extra diode. The led for the PC was connected to a wrong point, not changed yet.

    Some changes were made in the schematics and pcb design files before they were ordered, so the file section is no longer uptodate. One of the changes was another change in the instruction set...   New instructions to subtract two registers without storing the result, providing compare instructions. Logic instructions (and, or,...

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  • All design work has been done !

    roelh10/14/2017 at 16:55 0 comments

    All schematics and pcb designs are finished now. But I will do several checks before I send the PCB's out for production. (I already found some mistakes, can you find them too ?)

    Today I uploaded in the file section:

    • The schematics of all pcb's
    • A block diagram that clearly shows the main functions of the pcb's
    • An accurate description of pcb interface signals
    • Updated instruction list and architecture description

    This info should be enough to understand the design.

    I also posted the number of main components (327 relays). On the MEM pcb, I used BAW56 double-diodes because 1N4148 would cost me too much pcb area.

  • Speed Limit !

    roelh06/10/2017 at 20:43 2 comments

    Time to check the maximum reachable speed !

    The CPU needs 4 clock signals:

    • Phase 1 CLR
    • Phase 1 Activate
    • Phase 3 CLR
    • Phase 3 Activate

    There are also phase 2 and phase 4, but they have no clock signal, these phases are the relay 'layers' that follow the state of the relays that are switched by state 1 and 3.

    As the name implies, a CLR pulse clears a relay, and an Activate pulse can set a relay (if its input signal is true). But the CLR only disables the hold circuit of the relay. At the same time, the activate signal can be busy setting the relay, and even the circuits that follow the relay can already start switching while the CLR is still active ! So the clearing of a relay does not take time because it takes place at the same time as the activation (see technology file in the file section). The phase 1 CLR pulse falls within the phase 1 Activate pulse (so CLR can only be active if Activate is also active). And also, the phase 3 CLR pulse falls within phase 3 Activate.

    I did built a clock generator that has 4 relays (one for each clock signal), driven by a few transistors, and the transistors driven by a function generator. I attached the new clock to my test-setup (that has an ALU and a Register pcb). Phase 3 loads the ALU latch A with the data from register D, and phase 1 loads register D with the ALU output.

    On the test pcb, setting function to ADD and loading 1 in ALU latch B. This lets the ALU increment at each clock pulse.

    Well thats nice... what they call blinkenlights.... see the bytes incrementing at 3 places: at the ALU output, in register D, and at ALU input A.

    Yes and that sound.... Ohhhh...

    Cranking the frequency up, until errors begin to occur.... then a little bit down again where everything seems ok.... 136 Hz !!

    Power consumption around 600mA at 24 Volt. It's not really optimized for watts per megahertz....

    The other circuits in the CPU ( like instruction decoder, and PC incrementer ) will operate concurrently, and have the same technology as the ALU and registers (so they will reach the same speed). Most instructions use a single cycle, so the CPU could reach a speed of 136 instructions per second ! Probably will have to run it slightly slower for good reliability.

    The used relays have 2 mSec operating time. Relays with 1 mSec exist ( like IM06N ) but I found these too expensive. These could double the speed....

  • Main board layout

    roelh05/13/2017 at 15:30 0 comments

    Still working on the schematics. A lot of little details must be handled:

    • splitting clock signals, in order not to overstress relay contacts
    • program counter is 12 bits, add 4 bits and a selector knob to switch between several programs in two 64K x 8 flash chips
    • how to get the program in flash... provide connector for dedicated AVR-based programmer with RS232/USB connection to PC
    • The dedicated programmer should have buttons for manually composing an instruction and execute it
    • The clock signals must be made. Clock must be started and stopped.
    • User input buttons must be handled
    • The remaining pcb's (except main pcb) will be made smaller than the first ones, now I discovered that 10 x 10 cm boards are a lot cheaper than bigger ones (at certain pcb makers).
    • How to distribute the remaining circuits over several pcb's, and how to allocate signals on the 96 pin connectors

    The last point has great influence on the routing of the main board. So, the main board is routed first. The connector allocation can still be changed if needed (except for the existing register and ALU pcbs). Here is the current status:

    There are two rows of 6 connectors. At the front, there are 12 displays. The yellow signals must still be routed. But there will be more to do, since the schematics are not complete yet. This will keep me busy for a while...

    The ALU has now all 8 bits built, and is working after solving a few soldering issues.

  • PCB's for ALU and registers

    roelh04/16/2017 at 19:13 2 comments

    The first two PCB's have arrived ! This is the pcb for the registers:

    The pcb implements four 8-bit registers (registers C, D, X, Y). Only 8 bits (4 bits in 2 registers) are mounted. At the topside of the PCB, you see that each register has its own 8 LED's to indicate the contents. The pcb is labeled "REG1710" (top left) meaning the design is from 2017 week 10.

    The other PCB is the 8-bit ALU "ALU1710":

    Only 4 bits of the 8-bit ALU are mounted. The 4x4 relay section is the basic ALU, that includes two input registers (latches, to be honest). The sections with 2 relays are for the ADD-6 section and decimal correction. On the top of the pcb you see LEDs for input data, output data, function selection and flags. The ALU has the normal Load, AND, OR, XOR, binary ADD, but can also ADD decimally and convert BCD data to 7-segment display code. Subtraction needs help from outside of the ALU. It is done by inverting one of the register outputs (and setting the CY-input).

    The placement system is all diodes and relays on top, and the resistors on the bottom. Relays are surface mount types, this gives more space for routing at the bottom. Diodes are through-hole 1N4148. I did not use BAV99 or other SOT23 types (otherwise I could be accused of using transistors secretly ;). Mini-Melf were also avoided since they tend to roll away when you try to solder them. Some signal wires drive many circuits, in that case the diode is 1N4004 or similar.

    Of course, something was wrong. The connector DIN41612 was not close enough to the edge of the pcb (placement was based on the silkscreen of the footprint, I interpreted one of the silkscreen lines as the edge of the pcb, but that was wrong). I had to remove about 1mm of the pcb to make it fit. This destroyed only a few traces, that must be replaced by a wire.

    Schematics and gerbers of REG1710 and ALU1710 are in the Hackaday files section.

    I did built a simple test device. The ALU and REG pcb's can be connected to it. The 3x4 buttons transfer data from a register to the input A of the ALU and from the ALU to a register. The 8 buttons on top control data on input B (next to it are a CLR input B button and a CY-input button). The big knob selects one of the ALU functions, the function is displayed by one of the green LEDs.

    For the curious readers, here is the bottom side of the test device:

    And of couse, I tested my new pcb's. Found a small problem:

    It was intended that all diodes point in the same direction. But a few diodes on the ALU picked an older diode footprint, that had the silkscreen in the other direction. The result was a few diodes had to be reversed.

    After that was done, all assembled functions were working ! (But the tester does not test the second output ports of the registers).

    -------------------------------------------------------------------------------------------------------------------------------

    Some new instructions were added to the instruction set:

    - An instruction to load data from the program memory. The simulator has a unified memory, so the instruction was not needed there.

    - Added XOR with immediate value

    - Added a powerful instruction: Test a bit and branch. Within a single instruction, a single bit from a register pair can be tested, and a branch forward is done if the bit is 1 (or 0). In each register pair, the bits that can be tested are 0, 1, 2, 3, 4, 7, 15, 31. So this also replaces the clumsy sequence that was needed to test the upper bit of a value in a register. Instead of adding to the PC, this instruction can also conditionally add to register C. The branch forward has a reach of 31. In the instruction space, some space in the register-mode was sacrificed to make the test-and-branch possible.

    Work will continue with the details of the control functions, and planning the "backplane".

  • New project: NeuronZoo

    roelh01/05/2017 at 15:31 0 comments

    There was not much progress for the relay computer lately, mostly because I was working on a new project called NeuronZoo ! The NeuronZoo project is on Hackaday now !

  • Schematics of 3 pcb's

    roelh12/18/2016 at 20:42 0 comments

      There was not much progress the last months, mostly because of a new project that I hope to show soon.

      I have new ideas now about the distribution over several pcb's. Each pcb will have a DIN41612 96-pin connector to a backplane. For several subsystems, it is very easy to get over 96 signals, so reshuffling was needed. Also there is a limit to the number of relays that will fit on a pcb, the maximum is now 40. The size of the pcb's will be approx 10 x 14 cm.

      1. The register pcb implements 4 registers of 8 bits (32 relays). Of this pcb, 4 will be needed to implement the 7 16-bit registers (not all parts will be placed).
      2. The PC and decoder pcb. Implements 6 bits of the program counter (3 relays per bit), and circuits for decoding the registers. Two of these are needed for a 12 bit program counter, the decoder parts are not needed on the second pcb.
      3. The ALU pcb implements the 8 bit ALU, with both input registers A and B included. Two pcb's are needed for the 16 bit ALU.
      4. Instruction decoder
      5. Memory card. Two are needed, one for the program memory and one for the data memory. Includes the data shifter.
      6. The backplane will have connectors for all mentioned PCB's, and will hold the displays and buttons for the calculator. There will not be a straight 1-to-1 wiring of all connectors, every card will only work in its own position on the backplane.

      For pcb's 1,2 and 3 I did put complete schematics in the Hackaday file section. The PCB design is almost complete for registers and pc/decoder, and halfway for the ALU.

      The instruction set was again changed. Only half of the registers had logic instructions, this turned out to be impractical. Now, all registers have the same instructions. The price to be paid for this was that conditional instructions are now only for the PC and not for other registers (The ARM-like conditional instruction were not needed so much). In the Hackaday file section, the architecture and instruction list were updated. (My doc-to-pdf converter has trouble with the lines around tables, sorry about that).

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Bartosz wrote 11/08/2017 at 16:46 point

lufa ot contiki works on this machine?

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Yann Guidon / YGDES wrote 04/24/2017 at 22:30 point

It's looking better every day !

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Yann Guidon / YGDES wrote 12/20/2016 at 01:33 point

I looked at some of the PDF (webpages/logs are more practical though) and I appreciate the efforts you made to polish your design :-)

Now tell me : did you prototype some of the circuits you designed, with real parts ? Even a small subset... Relays can have surprising behaviours !

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roelh wrote 12/20/2016 at 14:55 point

Thanks for the compliment...

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roelh wrote 12/20/2016 at 14:58 point

No I did not test anything yet... When problems occur I hope to fix them with extra parts or wires on the pcb....

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Yann Guidon / YGDES wrote 12/20/2016 at 15:12 point

Hi :-)
I advise you against this approach: you might discover big problems after you have soldered everything. You would lose both all the relays and all the PCBs...

Testing small circuits, such as the ring oscillator, helped me uncover many issues I hadn't considered while drawing on paper. It made my design more reliable and I even ended up with configurations I had never seen in the litterature.


One example is the problem of fanout (which is, funnily, very similar to the issues in transistor-based circuits).

At least now I have characterised my parts beyond the mere indications of the datasheet and can estimate delays and consumption with good confidence.

Get that soldering iron and oscilloscope to work ! :-) Who knows what mistake you will find and how this will influence your next revision ? For example, how did you estimate the latches' feedback resistors and did you measure all the currents in all the driving combinations ?

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Alex Martin wrote 12/19/2016 at 23:43 point

Great project! I like the ambitious goal of "fastest relay cpu in the world".

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Yann Guidon / YGDES wrote 12/20/2016 at 04:29 point

I'll see if I can run #YGREC16 - YG's 16bits Relay Electric Computer faster ;-)

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Yann Guidon / YGDES wrote 12/18/2016 at 00:04 point

Ohhhhh... I just notice today, only now... Your sick trick for the 32-bits mode. Do you mind if it inspires me ? :-)

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roelh wrote 12/18/2016 at 20:57 point

Hi Yann, your question triggered me to update this project...

Yes, I like sick tricks. Of course you can use the 32-bit mode. What will be your instruction set ?

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Yann Guidon / YGDES wrote 12/18/2016 at 21:07 point

your "32 bits mode" looks to me like a "microvector", but I suspect is has already been used in other systems, such as the 68K.

For now, I have no target for this trick because 1) #AMBAP: A Modest Bitslice Architecture Proposal and #YASEP Yet Another Small Embedded Processor have too few registers 2) #F-CPU has a different approach (superscalar) 3) There is no need of dual-sized registers in pure RISC systems...

But it's good to know and I had actually considered an architecture with maybe 1K registers to create a "pseudovector" machine, using something along these lines.

For F-CPU this made me think about "binding" ou "pairing" execution units to increase throughput if the computations are identical in two globules... but this remains "single cycle", not "hold on a cycle and toggle a bit" :-)

Damn, there are so many possible combinations !

Regards :-)

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Yann Guidon / YGDES wrote 05/22/2016 at 22:30 point

The online JS assembler and simulator is sick.

You have done some awesome work ! I'm jealous :-P

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roelh wrote 05/23/2016 at 16:12 point

Thank you Yann. But the Javascript simulator is not very fast. The relay computer ifself would probably be faster...

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Yann Guidon / YGDES wrote 05/23/2016 at 16:57 point

At least I can compute Mandelbrot sets with my own simulator ;-)

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Winston wrote 04/13/2016 at 23:31 point

Very much looking forward to seeing (and hearing) this after you build it.

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Yann Guidon / YGDES wrote 04/18/2016 at 22:23 point

Yep. The noise it makes will sound like music...

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roelh wrote 05/22/2018 at 08:42 point

The computer is now partially built and working ! The CPU has its own website now:

http://www.enscope.nl/rrc

The website has a video with sound !

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