AMT Datasouth Accel-7350 Service Manual page 75

Port Explanation
(1) AL0-AL5(Input): Address input.
(2) AM8-AM15(3 state): Output address to DRAM for DMA.
(3) DRA8, DRA9(3 state) Output address to DRAM for DMA.
(4) AH18-AH22(Input) Address input.
(5) D0-D7(I/O): Data bus.
(6) XRD, XWR(Input): Read signal, write signal.
(7) XRAS, XCAS(3 state): Control access to DRAM of DMA.
(8) XRCONT(Output): Chip select for control ROM.
(9) XROPT(Output): Chip select for Option font ROM.
(10) XRFONT(Output): Chip select for font ROM.
(11) XGA2(Output): Chip select for BBG020.
(12) HREQ(Output): XHAK(Input): For DMA request and DMA start.
(13) INTHC(Input): To inhibit pin action at C motor position interrupt.
(14) SYNC(Input): For start timing of printing.
(15) SYSCLK(Input): 12.5 MHz clock.
(16) XRESET(Input): Reset signal.
(17) PINA1-24(Output, open drain): Pin waveform output.
Gate array BBG020
QFP, 100pin. Acts at 12.5 MHz. Access is possible with addresses 140000h-14003Fh.
Main Function
Controlling C motor rotation
Controlling LF motor rotation
Controlling ribbon motor rotation
Controlling head adjust motor rotation
Controlling MC motor rotation
Sensor interrupt output
C motor position interrupt output
Paper sensor input
Home sensor input
Cover open A input
Sensor input control
Buzzer control
74