USB-1808X TMR0 synchronous with OTRIG and OCLKI using Universal Library

[jwestra]

The datasheet for the USB-1808X specifies that the TMR outputs can be paced by the external clock OCLKI.

 

However, the Universal Library functions that use the TMR ports are pulse_out_start and pulse_out_stop, and unlike a_in_scan and a_out_scan, there is not EXTCLOCK option.

What is the proper way to pace timer output operations with an external clock using the MCC Universal Libary?

[Fausto]

Hello @jwestra.

There is no Universal Library function parameter option to specify using an external clock with the Timer; it is controlled by the hardware.  As stated in the USB-1808X User's Guide, the OCKLI (external clock input for an output operation) terminal becomes active on a rising edge.

Regards,

Fausto

[jwestra]

I don't observe this behavior on my board. We have a 12 kHZ 3V clock wired into OCLKI, and a 0.5 Hz 3.3V square wave wired into OTRIG, and we find that the TMR0 output is only synchronous to the OTRIG signal, and not OCLKI.