AM625: AM62x Clock Tree Tool

Kris Ganev

Part Number: AM625
Other Parts Discussed in Thread: SYSCONFIG, AM3358

Hello,

8 months ago I asked a question about the AM62x clock tree (https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1197498/am625-am62x-clock-tree-tool)

The clock tree tool does not show the ICSSM0 CORE_CLK and PaulM (https://e2e.ti.com/members/174422) told me that he will file a ticket to have it corrected in the next release.

It appears that the ICSSM0 clock tree has not been corrected, at least in the SYSCONFIG online tool (https://dev.ti.com/sysconfig/#/config/?args=--product%20%2Fmnt%2Ftirex-content%2Fsitara_ctt_1_0_1%2F.metadata%2Fproduct.json%20--device%20AM62x%20--part%20Default%20--package%20AMC%20--theme%20light%20--context%20system)

Thanks,

Kris

over 2 years ago

0 Mukul Bhatnagar over 2 years ago

TI__Guru* 84865 points

Hi Kris

Thanks. I will ping Paul M to respond to this and provide the latest status

Interested to understand how you are using PRU on AM62x?

Regards

Mukul

0 Kris Ganev over 2 years ago in reply to Mukul Bhatnagar

Intellectual 385 points

Hi Mukul,

We are using the PRU to drive a graphic LED display. The resolution up to 240 x 32 is not very high but the display is updated dynamically at 120 Hz and we have special graphic effects built in the driver.

We need to enable the spread spectrum (SSC) feature on the PLL that drives the PRU core in order to minimize the electromagnertic radiated emissions. However, I don't believe we can enable the SSC on the PRU default clock source, main PLL (PLL0), as it may interfere with many subsystems connected to it.

It looks like the PLL2 is also an option for the PRU core and we should be able to use it with SSC enabled but I need to come up configuration and the clock tree tool in the Sysconfig does not show the PRU core_clk.

We are already running the the graphic LED display driver in AM3358 PRU with enabled SSC, which allowed us to redice the radiated emissuions with 10 dB. The AM3358 clock tree design is quite convinient as the PRU core can be driven from the Display PLL, which is used for the DSS only and does not affect other subsystems. We dont use the AM3358 DSS, when we are running the PRU display driver, which works out perfectly.

Thanks,

Kris

0 Nick Saulnier over 2 years ago in reply to Kris Ganev

TI__Guru** 106760 points

Hello Kris,

To check: are you just reminding us about adding some things to the clock tree tool, or are you looking for how to figure out which clocks with which settings can be used to drive the PRU?

I have not had time to update these FAQs for AM62x, but the same concepts apply. If they are helpful or if you need any additional information, please let us know:
https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1041347/faq-pru_icssg-how-to-check-and-set-pru-core-frequency-in-ccs
https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1049800/faq-pru_icssg-how-to-check-and-set-pru-core-frequency-in-linux

Regards,

Nick

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AM625: AM62x Clock Tree Tool