I/O Connector - Radio Shack TRS-80 Service Manual

I/O CONNECTOR

In addition to serial interfaces, the MC-10 also
provides a full complement of CPU bus signals
that are accessible at the 34-pin cartridge con-
nector. This allows expansion of the MC-10 with
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
Table 1. I/O Connector Signals
Signal Name
GND
GND
D0
D1
D2
D3
D4
D5
D6
D7
R/W
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
E
SEL
RESET
NMI
+5v
GND
GND
– 15 –
external memory modules or ROM software
modules. Table 1 provides a complete list of the
signals and a brief description of each.
Description
Signal Ground
Signal Ground
CPU Data Bit 0
CPU Data Bit 1
CPU Data Bit 2
CPU Data Bit 3
CPU Data Bit 4
CPU Data Bit 5
CPU Data Bit 6
CPU Data Bit 7
CPU Read/Write Signal
CPU Address Bit 0
CPU Address Bit 1
CPU Address Bit 2
CPU Address Bit 3
CPU Address Bit 4
CPU Address Bit 5
CPU Address Bit 6
CPU Address Bit 7
CPU Address Bit 8
CPU Address Bit 9
CPU Address Bit 10
CPU Address Bit 11
CPU Address Bit 12
CPU Address Bit 13
CPU Address Bit 14
CPU Address Bit 15
Main CPU Clock (0.89 MHz)
Input to Disable Device Selection
Main Reset and Power-up Clear Signal to
the System
Non-Maskable Interrupt to the CPU
+5 volts (250 mA)
Signal Ground
Signal Ground