Cortex-M4 systick clock source

Discussion created by lpcware Employee on Jun 15, 2016
Content originally posted in LPCWare by diederikloos on Wed Jan 06 02:32:00 MST 2016
cortex-m4 running chibiOS
cortex-m0 running chibiOS
custom PCB

Hi all,

I have a question concerning the systick peripheral of the LPC4357-M4 processor. We are developing a multicore application, where the M0 is supposed to do most of the work, and disable the M4 as much as possible. We are running ChibiOS, and trying to replace the systick timer(which the LPC4357-M0 does not have) with the RIT.

The thing I was wondering is this:

I saw that the systick unit in the M4 processor allows an external clock source, and since lower clock means lower power consumption, would it be possible to use another clock source for the systick unit? How could I connect another clock source to systick? The Cortex-m4 device generic user guide does not say anything about connecting the external clock source, and I have not found this information in the LPC4357 datasheet. Probably this is written in some document somewhere, but I do not know where to look :)

Thanks in advance,