User's Manual

LEDs are controlled by the MARS-24 software
The MARS-24 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 specified 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
buffer. All outputs are 3V.
All the External input line pins will generate log messages when the state of
a pin changes, for example Info,External:Input 4 changed state to 0. The
ExternalInput() API function can also be called to read the state of all inputs
as a number. The inputs allow connection to either switches or any external
sensor which provides a contact closure or TTL compatible signal.
When designing external hardware, we strongly advise checking the design
with Magellan beforehand to verify that it will be electrically compatible.
This connector also includes the debug serial port of the CPU, which is used
as the system console. These pins are 3V levels only, so a proper RS-232
driver must be used externally if this connection is required.
Refer to Application Programmer’s Guide (40-01-000-DOC) for more
information.
MARS-24 USER MANUAL 63-70-006-DOC ver.1
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