Connecting To A Ttl Device - Matrox Iris GT Installation And Technical Reference

C o n n e c t i n g t o a T T L d e v i c e
To connect your Matrox Iris GT to a TTL device, you must first connect an
external pull-up resistor between them. The external pull-up resistor is needed
because TTL devices expect to be connected to a device that can provide power
(a sourcing device) and your Matrox Iris GT is a sinking device.
Connect an auxiliary output signal of your Matrox Iris GT and the device input
to an external pull-up resistor. In addition, connect the ground of the TTL device
and the ground of your Matrox Iris GT to a common ground.
The external pull-up resistor assures that when the output is disabled (off ), the
external resistor will pull-up the device's input to a positive voltage (+V).
Therefore, the device input is "on" when your Matrox Iris GT output is "off",
and vice-versa.
Matrox Iris GT
digital I/O and
power connector
AUX(USER)_IND_OUT0
1
Note that the output can
sink up to 100 mA.
C o n n e c t i n g e x t e r n a l d e v i c e s t o a u x i l i a r y o u t p u t s i g n a l s
Power
source
External
pull-up
resistor
1
GND
+5V
In 0
GND
TTL device
7 9