Epson SQ-1170, Service Manual

Page: 159 / 176

Table A-2. M A I N ) Table A-3. MAIN) (Cont.)
No. Signal Name Function
1 - + 5
+ 5
2 - + 5 + 5
3 - + 5
+ 5
4 - + 5 + 5
5 - + 5
+5
6 - + 5 +5
7 0
TXD
Transmit data
8
0 READY Ready to receive data
9 I RXD
Receive data
10 - NC No connection
11 0 RST Reset
12 0 INH
Inhibit
13 I Command request
14 WRRDY Write ready
15 Read request
16 0 WR
Write
17
0 RD Read
18 0 Cs chip select
19 - Signal ground
20 - Signal ground
21 - Signal ground
22 -
Signal ground
23 -
Signal ground
24 - Signal ground
25 0 A3 Address bus bit 3
26 0 A2 Address bus bit 2
27 0 A l Address bus bit 1
28 0 AO Address bus bit O
29 D7 Data bus bit 7
30 D6 Data bus bit 6
31 D5 Data bus bit 5
32 D4 Data bus bit 4
33 D3 Data bus bit 3
34 D2 Data bus bit 2
35 Data bus bit 1
36 DO Data bus bit O
Table A-3. M A I N )
No. Signal Name Function
1 - + 5 +5
2 - + 5 + 5
3 - + 5
+ 5
4 I ARE(3 Address request
5
0
6 0 PROG P-ROM chip select
7 0 RAM RAM chip select
8 0 CG CG ROM chip select
9 0 WR Write strobe
10 0
CGA I 8 address bit 17
11
0 RD
Read strobe
12 0 CGA13 CG address bit 13
13
0 CGA I 4 CG address bit 14
14
0 RAM 14
RAM address bit 14
15 0 CGA I 5 CG address bit 15
No.
Signal Name Function
16
0 RAM 15
RAM address bit 15
17 0 CGA16 CG address bit 16
18 0 RAM 16
RAM address bit 16
19 0
CGA17 CG address bit 17
20
0 AO
Address bit O
21 0 A l Address bit 1
22 0 A2 Address bit 2
23 0 A3
Address bit 3
24 0 A4
Address bit 4
25 0 A5
Address bit 5
26
0 A6
Address bit 6
27
0 A7
Address bit 7
28 0 A8 Address bit 8
29 - + 5 + 5
30 - + 5
+ 5
31 - Signal ground
32 - Signal ground
33 - Signal ground
34 0 6
Program address bit 16
35
0 MREQ
Memory request
36
0 5
Program address bit 15
37 0 4 Program address bit 14
38 0 CG address bit 22
39 0 CGA21 CG address bit 21
40 0 CG address bit 20
41 0 CGA I 9
CG address bit 19
42 0 3
Program address bit 13
43
0 RAMAl 3
RAM address bit 13
44 0 A9 Address bit 9
45 0 A lO Address bit 10
46 - NC Not connect
47 0 Al 1
Address bit 11
48 - NC
Not connect
49 0 Al 2
Address bit 12
50 D7
Data bus bit 7
51
D6 Data bus bit 6
52 D5 Data bus bit 5
53 D4
Data bus bit 4
54 D3
Data bus bit 3
55
D2 Data bus bit 2
56 Data bus bit 1
57 DO Data bus bit O
58 - Signal ground
59 - Signal ground
60 - Signal ground
A-3