User's Manual

4.2.2 USER I/O INTERFACE CONNECTOR
The MARS-24E has an external interface connector called the USER I/O. This provides a number of digital input
and outputs points. These can be used under application control to connect to external devices, such as buttons
and lights.
The connector is an IDC 20 pin male.
The pins are used as follows:
Pin Number Direction Function
1 - 5V at up to 200mA
2 Out Fault alarm signal
3 Out Debug serial port transmit
4 Out SPI port output
5 Out SPI port clock
6 Out External output line 0
7 Out External output line 1
8 Out External output line 2
9 Out External output line 3
10 Out External output line 4
11 In Debug serial port receive
12 In External input line 0
13 In External input line 1
14 In External input line 2
15 In External input line 3
16 In External input line 4
17 In External input line 5
18 In External input line 6
19 - Ground
20 - Ground
All the External output line pins can be controlled using the ExternalOutputState() and ExternalOutputPulse() API
commands using the number speci ed in the table. For example, ExternalOutputState(3,1) would turn on the
output on pin 9. Note that the outputs are intended to drive a simple LED indicator or provide a control signal to
a more powerful external bu er. All outputs are 3V.
18 63-70-006-DOC 07-Jul-07
User Manual
MARS-24E