Casio QT-2000 Service Manual

— 21 —5-4. LSI pin description1. CPU (uPD70108HGC-16-3B6)Pin No. Name Description I n / O u t1 A18/PS2 Address bus (A18) / Processor status Out2 A17/PS1 Address bus (A17) / Processor status Out3 A16/PS0 Address bus (A16) / Processor status Out4 A15 Address bus (A15) Out5 VDD Power source -6 VDD Power source -7 GND GND -8 GND GND -9 IC Internaly connect (GND) -10 A14 Address bus (A14) Out11 A13 Address bus (A13) Out12 A12 Address bus (A12) Out13 A11 Address bus (A11) Out14 NC Not used -15 A10 Address bus (A10) Out16 A9 Address bus (A9) Out17 A8 Address bus (A8) Out18 AD7 Address / Data bus (AD7) In/Out19 AD6 Address / Data bus (AD6) In/Out20 AD5 Address / Data bus (AD5) In/Out21 AD4 Address / Data bus (AD4) In/Out22 AD3 Address / Data bus (AD3) In/Out23 AD2 Address / Data bus (AD2) In/Out24 AD1 Address / Data bus (AD1) In/Out25 AD0 Address / Data bus (AD0) In/Out26 NC Not used -27 NC Not used -28 NMI Non-maskable interrupt (GND) -29 INT Maskable interrupt In30 CLK System clock (16MHz) In31 GND GND -32 NC Not used -33 GND GND -34 GND GND -35 RESET Reset In36 READY Ready signal In37 _POLL Polling signal In38 _INTAK Interrupt acknowedge Out39 ASTB Address strobe Out40 NC Not used -41 _BUFEN Buffer enable Out42 BUF_R/W Buffer read/write enable Out43 IO/_M IO / memory select signal Out44 _WR Write strobe Out45 HLDAK Hold acknowlege Out46 NC Not used -47 HLDRQ Hold request In48 _RD Read strobe Out49 S/_LG Small / Large select (5V) -50 LBS0 Not used -51 A19/PS3 Address bus (A19) / Processor status Out52 NC Not used -