Epson SQ-B50/2550 Technical Manual page 268

REV.-A
Table A-4. E05A21 AA Terminal Functions
Pin No. Terminal
I/O Description
1 - 3
P2(AD 17)- I/O Address bus 17 - 19
PO(AD19)
-
ON LINE switch read (interrupt) 4 IIN I
- -
Cartridge install signal 2 (reset signal) 5 CAR2 I
6 CAR1 I Cartridge install signal 1 (reset signal)
- -
Power ON reset signal output 7 ROUT 0
8 VSS(GND)
-
GND
9 THLD I
Reset signal generator thleshold lebel input
10 DISC 0
Reset signal generator discharge control
1 1 CPU
I CPU initialize signal
12 MLT
I
13 RD
I Read strobe
14 WR
I Write strobe
15 ALE
I Address latch enable
16 - 23 A 15 - A8
I Address bus 15 - 8
24
VSS(GND) - GND
25 - 32 AD7 -ADO
I/O Multiplexed lower address bus 7 - 0 / data bus 7 - 0
33-39 AO-A6
I/O
Address bus 0 - 6
40 VDD(+5V)
-
Power sourse
41 A7
I/O
Address bus 7
,
42 -47 BO- B5 0 Bank change signal 0 - 5
48
BANK
0
Bank signal for external CG board
49 BNK80
0 Bank signal for external CG board (KCG area)
50
CSBOO
0
Decoded Chip Select signal (CGO area)
51
CSB40 0 Decoded Chip Select signal (CG 1 area)
52 CSBCO 0 Decoded Chip Select signal (KCGO area)
53 CSBDO 0 Decoded Chip Select signal (CAO area)
54 CSBEO 0 Decoded Chip Select signal (CA 1 area)
55
CSBFO
0
Decoded Chip Select signal (RAM area)
56 RAM 0 RAM bank change signal
57 VDD(+5V) - Power sourse
58 PROI 0
Internal program ROM enable signal
59 PROE 0
External program ROM enable signal
60- 64 MMIO 00- 0
Memory Mapped I/O signal
MMIO 04
A-10