CCM Output Generation

adam_smartind — Fri, 22 Jan 2021 08:32:11 GMT

Hello,

I've been reading MX8MN RM for a while and try to figure out a way to generate CCM_CLKO at GPIO.

Also, I've read the following posts covering the CCM_CLKO topics

https://community.nxp.com/t5/i-MX-Processors/i-MX8MM-CCM-OUTPUT/td-p/1179744

https://community.nxp.com/t5/i-MX-Processors/clock-generation-on-CCM-CLKO2/m-p/628613

https://community.nxp.com/t5/i-MX-Processors/i-MX8M-Mini-definition-of-CCM-CLKO-2-1-pins/m-p/966969

https://community.nxp.com/t5/i-MX-Processors/CCM-CLKO-as-CLK-input-for-peripheral/m-p/971263

My first question is that MX8MN RM gives two different ways to configure CCM_CLKO.

1. Through CCM Mem Map Regs

CCM_CLKO locates in Slice 116/117 and can be accessed through CCM Mem Map Regs

2. Through CCM Analog Mem Map Regs

Which one should be use or what are the differences between these two register sets?

The second question is can I use a CLK buffer to deliver the CCM_CLKO to other peripherals?

In this post https://community.nxp.com/t5/i-MX-Processors/i-MX8MM-CCM-OUTPUT/td-p/1179744

Igor wrote that the stability is defined by the used crystal and it seems this CCM_CLKO can serve as a CLK source feeding other peripherals.

But in other posts,

https://community.nxp.com/t5/i-MX-Processors/CCM-CLKO-as-CLK-input-for-peripheral/m-p/971263

https://community.nxp.com/t5/i-MX-Processors/i-MX8M-Mini-definition-of-CCM-CLKO-2-1-pins/m-p/966969

guys were saying that CCM_CLO is just for monitor use.

So which saying is true?

Thanks

Re: CCM Output Generation

igorpadykov — Fri, 22 Jan 2021 10:17:18 GMT

Hi adam_smartind

>Which one should be use or what are the differences between these two register sets?

CCM_ANALOG_ANAMIX_PLL_MNIT_CTL should be used.

>The second question is can I use a CLK buffer to deliver the CCM_CLKO to other peripherals?

this depends on requirements of connected peripherals, strictly speaking CCM_CLKO was
not characterized for frequency stability and can not be used for very stable clock.
For example CLKO1 is used for camera on J802 connector p.11 SPF-31407 i.MX8M Nano Baseboard schematic

Design Files for the i.MX 8M Nano Evaluation Kit (8MNANOD4-EVK)

Best regards
igor

topic CCM Output Generation in i.MX Processors

CCM Output Generation

Re: CCM Output Generation

Design Files for the i.MX 8M Nano Evaluation Kit (8MNANOD4-EVK)