Matrox Rapixo CXP - Timers; Trigger; Quadrature Decoder

42 Chapter 4: Matrox Rapixo CXP hardware reference
Timers
Matrox Rapixo CXP has 4 16-bit timers, which operate on a specified clock source.
Timer output signals allow you to control the exposure time and other external
events related to the video source (such as a strobe). A timer output signal can be
output on any of the auxiliary output signals or auxiliary I/O signals in output
mode. A timer output can also be sent to a video source via the CoaXPress trigger
output signal.
The timers can use one of the following as a clock source:
• A 125MHz internal clock source.
• A clock based on the output of another timer set in continuous mode.
• A clock based on the HSYNC or VSYNC signal of your camera.
• A clock based on the pixel clock signal of your camera/
To route a timer output on an auxiliary signal, use the MIL-Lite function
MdigControl() with M_IO_SOURCE + M_AUX_IOn set to M_TIMERn. To
set up a timer, use MdigControl() with M_TIMER_....
Trigger
You can use as a trigger any of the auxiliary input signals (or auxiliary I/O signals
in input mode), or the CoaXPress trigger input signal. A trigger signal can be used
to initiate image acquisition or prompt an on-board event.
To enable grabbing upon a trigger, use the MIL-Lite function MdigControl() with
M_GRAB_TRIGGER_STATE. To set the signal used to trigger the grab, use
MdigControl() with M_GRAB_TRIGGER_SOURCE. To start a timer upon a
trigger, use MdigControl() with M_TIMER_TRIGGER_SOURCE.
Quadrature decoder
Matrox Rapixo CXP features 4 quadrature decoders. They are used to decode
quadrature input received from linear or rotary encoders with a quadrature output.
A rotary encoder is a device that provides information about the position and
direction of a rotating shaft (for example, that of a conveyor belt); a linear encoder
is a device that provides information about the position and direction of a moving
sensor along a scale. Encoders with quadrature output transmit a two-bit code
(also known as Gray code) on two pairs of LVDS wires for each change in position