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ECM-16/TTL Pilot-1 computer

A project log for ECM-16/TTL homebrew computer

16 bit Computer made from ttl logic chips

pavelPavel 11/16/2021 at 09:060 Comments

UPD: I created a new project dedicated exclusively for this Pilot-1 cpu.

This is fully functional, albeit severely limited, automated calculating machine.

It can be viewed as having a kind of Harvard architecture, as it has all instructions in ROM, and data is in RAM (registers actually).

The limitations are -- the program can be max 16 instructions long, and there are  only 8 registers where data can be operated on.

As all the registers' data are visible on register display, it presents a good view in process of calculation -- all those lights blinking!

This machine features full Main ALU together with Register File, completing the Calculating Core, with slapped-on Provisional Control Unit and HROM, that makes it whole.

It is a good milestone towards full-fledged computer, that supposed to have full addressing and  control circuitry, as well as proper memory and I/O. As it is now, it gives some taste of what it will become some day.

Here is block diagram of this contraption:

And here is what it looked like when I first assembled it fully and tried to run it:

There are several issues, mostly due to some unexpected behaviour of HROM board, and probably there are some bugs in the control board causing intermittent resets.

The HROM had been lying around for a year, and it seems like it sustained some damage causing intermittent shorts on data line B. The glitches on the control board also haven't gone away.

I hope, in the near future I'll weed out all these bugs, and system will work fully as intended. After this, next phase will be building memory access adder and registers, and combining them into single unit. In parallel, there will be finalisation of the instruction set and design of control logic.

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