RE: what is the propagation delay through ppi

Ole Bauck — Wed, 14 Sep 2016 12:47:57 GMT

If you take the ppi delay alone it is about 1 clock cycle which equals 62.5ns. You can actually test this by using the code here and compare the pulse when using ppi to clear the timer instead of shorts.

If the peripheral you are using require some resources that are not on you will have to start these first. As the product specification says (part 3.4.2.2 System ON mode):

(…) The PPI task response will vary depending on the resources required by the peripheral where the task originated. The resources that could be involved are:

1V7 with the startup time t1V7

1V2 with the startup time t1V2

One of the following clock sources

RC16 with the startup time tSTART,RC16

XO16M/XO32M with the startup time the clock management system tXO

but since you say that you don’t go into low power mode (__WFE() or sd_app_evt_wait) you should not need to worry about this.

Since you are using pin in and out event, the impedance on the pin may also affect the response. Typical pin capacitance is 4pF and typical pull-up resistance is 13KOhm. This circuit will have a rise and fall time.

What is the actual time you are measuring and how are you measuring it?