19 Sep
1998
19 Sep
'98
12:44 p.m.
At 02:49 PM 9/19/98 -0700, Sam wrote:
On Sat, 19 Sep 1998, Tony Duell wrote:
Today I plugged in the front panel and a Cromemco ZPU. It worked! The
address LEDs 15, 14 and 13 are sequencing in a binary pattern. I don't
know what this means, but at least it shows life. I got the same results
with another ZPU. I can single-step it and see different stuff happening,
but I have no idea what its doing. I buried my friggin IMSAI manual in a
box a few weeks back.
No memory installed? It is executing a RST 7 (0FFH) which pushes the
current address onto the stack and jumps to 038H (070 octal), and finding
yet another 0FFH there, repeats the exercise forever... You are seeing the
stack pointer reflected in the lights when running...
It's a good sign.
-jim
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