Acorn BBC Master Series - Page 59

Master Series Service Manual
PL4 user port
20-way IDC
1 +5V 2 CB1
3 +5V 4 CB2
5 0V 6 PB0
7 0V 8 PB1
9 0V 10 PB2
11 0V 12 PB3
13 0V 14 PB4
15 0V 16 PB5
17 0V 18 PB6
19 0V 20 PB7
PL5 1MHz bus
34-way IDC
1 0V 2 R/notW
3 0V 4 1E
5 0V 6 notNMI
7 0V 8 notIRQ
9 0V 10 notPGFC
11 0V 12 notPGFD
13 0V 14 notRS
15 0V 16 audio in/out (see LK1)
17 0V 18 D0
19 D1 20 D2
21 D3 22 D4
23 D5 24 D6
25 D7 26 0V
27 A0 28 Al
29 A2 30 A3
31 A4 32 A5
33 A6 34 A7
54 Issue 1