This is one of the first computers I played with. It's on my list of things to be resurrected.
I scanned the MCS-80 System Design Kit Users Guide. It's big (17 megs).
Here's an article from Electronics Australia, July 1977.
The SDK-80 came with two 2708 EPROMs. I dumped parts of it waybackwhen, using my MEK6800D2 kit, and found that it's a copy of Li-Chen Wang's Palo Alto Tiny BASIC as published in Dr Dobbs, May 1976. There are some changes though.
My dump: 31 90 5f 3e ff c3 69 06 e3 ef be c3 68 00 3e 0d f5 3a 14 3c 87 c3 a3 06 cd 85 03 e5 c3 41 03 57 7c ba c0 7d bb c9 41 4e 1a fe 20 c0 13 c3 28 00 0000 31 90 5F LODI SP, 5F90 0003 3E FF LODI A, FF 0005 C3 69 06 JMP 0669 ST1 * 0008 E3 XCHG HL,(SP) 0009 EF RST 7 0028 / SS1 / IGNBLK 000A BE CMP M 000B C3 68 00 JMP TC1 000E 3E 0D LODI A, 0D * 0010 F5 PUSH AF 0011 3A 14 3C LD A, 3C14 OCSW 0014 87 IOR A 0015 C3 A3 06 JMP 06A3 OC2 * 0018 CD 85 03 CALL 0385 EXPR2 001B E5 PUSH HL 001C C3 41 03 JMP 0341 EXPR1 001F 57 CHAR 'W' * 0020 7C LOD A,H 0021 BA CMP D 0022 C0 RET NZ 0023 7D LOD A,L 0024 BB CMP E 0025 C9 RET U 0026 41 4E CHAR 'AN' * 0028 1A LD A,(DE) 0029 FE 20 CMP ' ' 002B C0 RET NZ 002C 13 INC DE 002D C3 28 00 JMP 0028 SS1
October 2015: I
completed the dump of the first EPROM. You know what's amazing? I've had these EPROMs since the eighties
and they were not new then and the code is still intact. And they don't even have stickers on the windows.
I think I can conclude that this Tiny Basic was not intended for the SDK-80. The SDK-80 has RAM from 0x1000 to 0x13FF while this port sets up the stack at 0x5F90 and has OCSW at 0x3C14. This sort of feels like a system with (space for) 8K ROM (0x0000 to 0x1FFF) and 16K RAM (0x2000 to 0x5FFF) -- but I could be wrong of course...
hits since 2015-07-16.
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