How to perform timed output on a port

• version

  1.1.1

• scope

  Example.

  This code is provided as example code for a user to base their code on.

• description

  How to perform timed output on a port

• boards

  Unless otherwise specified, this example runs on the SliceKIT Core Board, but can easily be run on any XMOS device by using a different XN file.

An output operation can be performed on a port at a specific time with respect to its clock.

The following statement performs a timestamped output, outputting the value 0 to the port toggle_port and reading into the variable count the value of the port counter when the output data is driven on the pins.

toggle_port <: 0 @ count;

The statements

count += 3;
toggle_port @ count <: 1;

cause the port to wait until its counter equals the value count+3 and then drive its pin high. The next two statements delay the driving of the pin low by 2 clock periods.

count += 2;
toggle_port @ count <: 0;

The ability to control output on a port can also be achieved using a timer resource from the processor. Note however that the ports time operator is 16-bit whereas the processor timer resource is 32-bit. See example “How to control port output data rates with timers” for further information.