SIM4-01 and MP7 programmer cards

dwight dkelvey at
Thu Feb 25 18:58:30 CST 2016

I know this is kind of obscure but I thought I'd see if anyone was interested

in the program I wrote.

It is for the SIM4-01 and MP7 boards.

Normally these two boards would plug into a mother board called the MCB4

but I've seen a few cases on the web that they'd been wired from socket to socket.

Normally they'd be used with the A0540, A0541 and A0543 EPROMs to program

1702As on the MP7 cards.

The data for the proms would be sent to the SIM4 board over a serial current

loop at 110 baud. It was in what Intel called a BPNF format. Each bit of the

byte would be sent as either a P or N for the 8 bit data width. This extends the

programming time for a 1702A from a little over 2 minutes to over 7 minutes.

I still use my SIM4 setup to occasionally program one or two 1702A for friends.

Recently, I was given a large number to program. I did these slowly a 7 minutes

each. I soon realized I could write some 4004 code to copy the EPROMs.

I'd only need to down load the first one at 7 minutes and the reset at 2 minutes each.

There were some issues, the SIM4-01 only has 256 nibbles of memory,

unlike the SIM4-02 that has more. There was code for the larger board in

one of the manuals on bitsavers but the code was written for the larger memory.

I needed to make a two pass system and it expected there to be a copy from

socket. This required a complete rewrite.

The code in the manual did both the 1702 and the 1702A. I really only needed

the 1702A part. Non-A parts are as rare as hen's teeth.

I also wanted to add some code to do a RAM test since I would use 100% of

the character RAM.

I wanted to do a March C test but because of size had to settle for a simple

data/data complement stuck at test.

I wanted every thing to fit into a single 1702A. My first pass code was over

300+ bytes. I needed to reduce down to 256 bytes. I worked on the code

for about a week and finally got it down to 252 bytes.

I use a simple simulator that I wrote because I don't understand the simulators

on the web enough to connect things to I/O actions. I needed to simulate

a master EPROM and a copy to EPROM as well as the test switch for sequencing

when to put each EPROM in the sockets. There were of course status lights

so a person knew what stage they were at.

Anyway, I created a program I call onecopy. If anyone is interested in it,

I can send them a binary or intel hex file.


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