SIT board



The SIT board is an original extension board designed for The Irritating Maze game. It connects to the JAMMA edge, to the output port (CON1), and to the various peripherals needed by the game (trackball controller, lights, air compressor, ticket dispenser...).

The additional outputs are organized as:
 * 11x 2A sink outputs made with D1764 60V NPN Darlington transistors (space for 5 more).
 * 8x 500mA sink outputs made with a 2083 Darlington array through resistors.

The 24V input (CON3) is only used for the flyback diodes on the 2A transistors.

The inputs from the go through a HC14 inverter except one line (reset ?) before going to the EPM7128 CPLD (the same type used in Metal Slug X - Super Vehicle-001) which contains at least 2 quadrature decoders and counters, and one 16 bit SIPO register with latch (and maybe another 8bit one ?).

=I/O=

The register is used for output control by the special system ROM.

If dipswitch 2 ON: Card dispenser connected

=Code=

Special system ROM routines:


 * $1B212: clear outputs 8,0, x16 (32 writes, latch all outputs low)
 * $1B322: Read trackball X
 * $1B342: Read trackball Y
 * $1B5C2: Air jet
 * $1B494: Set outputs:

ROM:0001B494 sub_1B494: ROM:0001B494                moveq   #0,d7           ; Start off with D7 cleared      0000 0000 0000 0000 ROM:0001B496                tst.b   $B22(a5)        ; $10FE22: FLASH LAMP (flag) ROM:0001B49A                bne.w   loc_1B4A2 ROM:0001B49E                bset    #$E,d7          ;                                0a00 0000 0000 0000 ROM:0001B4A2 ROM:0001B4A2 loc_1B4A2: ROM:0001B4A2                move.b  $B21(a5),d0     ; $10FE21: COLOR LAMP (2 bits, 000000xx) ROM:0001B4A6                beq.w   loc_1B4B2 ROM:0001B4AA                ror.w   #4,d0 ROM:0001B4AC                andi.w  #$3000,d0 ROM:0001B4B0                or.w    d0,d7           ;                                0abb 0000 0000 0000 ROM:0001B4B2 ROM:0001B4B2 loc_1B4B2: ROM:0001B4B2                tst.b   $B20(a5)        ; $10FE20: SIDE LAMP (flag) ROM:0001B4B6                beq.w   loc_1B4BE ROM:0001B4BA                bset    #$B,d7          ;                                0abb c000 0000 0000 ROM:0001B4BE ROM:0001B4BE loc_1B4BE: ROM:0001B4BE                tst.b   $B1F(a5)        ; $10FE1F: TRACK BALL LAMP (flag) ROM:0001B4C2                beq.w   loc_1B4CA ROM:0001B4C6                bset    #$A,d7          ;                                0abb cd00 0000 0000 ROM:0001B4CA ROM:0001B4CA loc_1B4CA: ROM:0001B4CA                move.w  $B1C(a5),d0     ; $10FE1C: TIMER LAMP (word, 10 bits, 000000xx xxxxxxxx) ROM:0001B4CE                andi.w  #$3FF,d0 ROM:0001B4D2                or.w    d0,d7           ;                                0abb cdee eeee eeee ROM:0001B4D4                tst.b   $B29(a5)        ; $10FE29: ? (flag) ROM:0001B4D8                beq.w   loc_1B4E0 ROM:0001B4DC                bset    #$F,d7          ;                                fabb cdee eeee eeee ROM:0001B4E0 ROM:0001B4E0 loc_1B4E0: ROM:0001B4E0                move.b  $B23(a5),d0     ; Copy of $380001 ROM:0001B4E4                moveq   #$F,d1          ; Shift out 16 bits ROM:0001B4E6 ROM:0001B4E6 loc_1B4E6: ROM:0001B4E6                andi.b  #$31,d0         ; Mask out latch, clock and data bits (00xx000x) ROM:0001B4EA                lsr.l   #1,d7 ROM:0001B4EC                bcc.w   loc_1B4F4 ROM:0001B4F0                bset    #1,d0           ; Set data bit (00xx00dx) ROM:0001B4F4 ROM:0001B4F4 loc_1B4F4: ROM:0001B4F4                move.b  d0,($380001).l  ; Output data ROM:0001B4FA                nop ROM:0001B4FC                nop ROM:0001B4FE                bset    #2,d0           ; 00xx01dx ROM:0001B502                move.b  d0,($380001).l  ; Set clock high ROM:0001B508                dbf     d1,loc_1B4E6    ; Loop for all bits ROM:0001B50C                nop ROM:0001B50E                nop ROM:0001B510                andi.b  #$31,d0         ; Mask out latch, clock and data bits (00xx000x) ROM:0001B514                bset    #1,d0 ROM:0001B518                move.b  d0,($380001).l  ; Set data bit (00xx001x) ROM:0001B51E                nop ROM:0001B520                nop ROM:0001B522                bset    #3,d0 ROM:0001B526                move.b  d0,($380001).l  ; Set latch bit (00xx101x) ROM:0001B52C                nop ROM:0001B52E                nop ROM:0001B530                andi.b  #$31,d0         ; Clear (00xx000x) ROM:0001B534                move.b  d0,($380001).l ROM:0001B53A                 rts