Suggested 2068 ROM Changes

I am sending copies of the proposed changes to the TS2068 home ROM to those shown on the end of the listing. After receiving comments I’ll send out copies and have the results published. If you have any comments, corrections, or additions please let me know.

I am also collecting corrections to the extension ROM. The Utility Function Dispatcher is a disaster and we have no example of external bank switching, etc. This makes corrections a bit harder.

I am now retired. Sales of the GESSO products are now mostly through Sunset Electronics in San Francisco. I will continue to support the Timex/Sinclair products.

Our clubs are doing fairly well. I have made the source for the TS2068 available to other club members and there has been some interest.

Proposed HOME ROM Fixes

Fix for Oliger EPROM Programmer (see May 1985 Syncware p. 14)

002B 84             DB 84H
002C 87             DB 87H
002D 8B             DB 8BH
002E 8D             DB 8DH
002F 92             DB 92H

NMI Fix

006D 2801           JR Z,0070H

DELETE delay timing

0351 010100         LD BC,0001H
0354 0B             DEC BC
0355 79             LD A,C
0356 B0             OR B
0357 20FB           JR NZ,0354H
0359 F1             POP AF
035A 18D2           JR 002EH

Optional turn on message (last character add 80h)

1118 Property of Bob
1128 Orrfelt.........
1138 ................
1148 ..

INT -65535 etc. errors

33F1 F5            PUSH AF
33F2 3C            INC A
33F3 B3            OR E
33F4 B2            OR D
33F5 C2E435        JP NZ,35E4H
33F8 C3EF35        JP 35EFH

35E2 1812          JR 35FEH
35E4 F1            POP AF
35E5 77            LD (HL),A
35E6 23            INC HL
35E7 73            LD (HL),E
35E8 23            INC HL
35E9 72            LD (HL),D
35EA 2B            DEC HL
35EB 2B            DEC HL
35EC 2B            DEC HL
35ED D1            POP DE
35EE C9            RET
35EF F1            POP AF
35F0 2B            DEC HL
35F1 3691          LD (HL),91H
35F3 23            INC HL
35F4 3680          LD (HL),80H
35F6 3C            INC A

35F9 FFFFFFFF
35FD FF

More for EPROM Programmer

37B8 D9            EXX
37B9 212B00        LD HL,002BH
37BC 85            ADD A,L
37BD 6F            LD L,A
37BE 6E            LD L,(HL)
37BF 2636          LD H,36H
37C1 D9            EXX
37C2 AF            XOR A
37C3 C9            RET
37C4 00            NOP

USR Chunk Selection

389F E660          AND 60H
38A1 281B          JR Z,38BEH
38A3 D640          SUB A,40H
38A5 FAB738        JP M,38B7H