new retro computing

From: Ben Franchuk <>
Date: Sun Jul 21 14:07:00 2002

Eric Smith wrote:

> Why not use the Atmel or Xilinx reprogrammable parts? They will work
> fine with Altera FPGAs. They don't have special programming requirements,
> so you can burn them yourself, over and over without spending more money.

Since I live in "The Great White North" all electronic components have to be
ordered thru the mail and information pulled off the web. Programing the FPGA is
not a problem for testing as I have a download cable. Right now I have about 20
pages of TTL schematics that need to tested for the CPU design once I re-write a
assembler for new opcodes. About 2 ALU logic boards and 3 Control boards if I
used TTL. Other than finding 16x4 Non Inverting RAM (low power) I can still get
all the LS parts needed, but I am using the FPGA becase it handy.

> Also, I don't see any reason why you'd need a microcontroller to be
> involved. Some of my FPGA designs read extra data from their own config
> PROM, with no microcontroller involved. I just hooked up the config pins
> to some I/O pins. During config, all the I/O pins are high-Z, so they
> don't interfere with the configuration.

Nice but I am emulating a PDP-8/TTY style computer system.Built in Bootstrap is
the primary input method. Even if I used non-volitile memory I still have to
have "nnnn nnnn ?" entered from the bootstrap device.

Thanks again for your help.
Received on Sun Jul 21 2002 - 14:07:00 BST

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