topic Re: CCM_CLKO as CLK input for peripheral in i.MX Processors

CCM_CLKO as CLK input for peripheral

thorben — Fri, 26 Jul 2019 08:01:51 GMT

Hi,

on the iMX8M mini, can we use CCM_CLKO from Clock Control Module (CCM) as an input clock for some external peripheral on our PCB or is CCM_CLKO just meant to be a test/control clock output and not intended to serve as an input clock?

Regards,

Thorben

Re: CCM_CLKO as CLK input for peripheral

Rita_Wang — Fri, 02 Aug 2019 05:17:17 GMT

Could you tell us which product are you using?

Re: CCM_CLKO as CLK input for peripheral

thorben — Fri, 02 Aug 2019 07:43:43 GMT

I'm sorry, I only added the processor type to the tags. It's a iMX8M mini.

Re: CCM_CLKO as CLK input for peripheral

Rita_Wang — Fri, 02 Aug 2019 09:38:09 GMT

I have sent your question to our expert team, when I get update I will send to you as soon as possible.

Re: CCM_CLKO as CLK input for peripheral

Rita_Wang — Tue, 06 Aug 2019 03:26:20 GMT

I got the update from our expert, Please refer to the register definition. OFFSET: 0x128

Re: CCM_CLKO as CLK input for peripheral

thorben — Tue, 06 Aug 2019 05:41:38 GMT

Thank you. I already know these values from the reference manual. I want to know if we can use it as an clock input for external peripheral? Does this output have for example jitter? If it's just a monitor clock and it maybe has some jitter, we wouldn't be able to use it.

Re: CCM_CLKO as CLK input for peripheral

Rita_Wang — Fri, 09 Aug 2019 02:36:02 GMT

We are confirming it for you.

Re: CCM_CLKO as CLK input for peripheral

Rita_Wang — Mon, 12 Aug 2019 08:22:18 GMT

Hello, I got the update from our expert team.

Checked with our SOC, it's not recomended to drive external device by CLKOUT. Jitter may also relate to PCB layout.

The CLKOUT is not designed for the purpose. It's just for monitor.

Hope this can do help for you.

Have a nice day

Rita