AM623: Enable CLOCKOUT0

Gireesh Hiremath

Intellectual 405 points

Part Number: AM623

Tool/software:

Hi,

I need to enable clock (range from 6MHz to 24MHz) from the pin A18 to camera module

and dts as below

refclk1_out_pins: refclk1-out-pins {
pinctrl-single,pins = <
AM62X_IOPAD(0x01f0, PIN_OUTPUT_PULLUP, 5) /* (A18) EXT_REFCLK1.CLKOUT0 */
>;
};

&k3_clks {
refclk1_out {
assigned-clocks = <&k3_clks 157 67>;
assigned-clock-rates = <25000000>;
pinctrl-names = "default";
pinctrl-0 = <&refclk1_out_pins>;

status = "okay";
};

};

not able to see any clock on line, please give suggestion.

Thanks,

Gireesh Hiremath

10 months ago

0 Bin Liu 10 months ago

TI__Guru**** 174411 points

Hi Gireesh,

Gireesh Hiremath said:
assigned-clocks = <&k3_clks 157 67>;

I don't have to time to test it right now, but I am wondering if the id '67' should be '33' instead.

According to https://software-dl.ti.com/tisci/esd/latest/5_soc_doc/am62x/clocks.html, clock 67 is "DEV_BOARD0_MCU_EXT_REFCLK0_OUT", while clock 33 is 'DEV_BOARD0_EXT_REFCLK1_OUT'.

0 Gireesh Hiremath 10 months ago in reply to Bin Liu

Intellectual 405 points

Hi Liu,

I tried with ID 33 but I see only 0v6 on the line, not clock.

as of now it is not connected to any device

I feel no need of parent clock info for the CLKOUT0 pin

Regards,

Gireesh Hiremath

0 Bin Liu 10 months ago in reply to Gireesh Hiremath

TI__Guru**** 174411 points

Hi Gireesh,

I looked into the TRM and Datasheet about pin A18 in mode 5 (CLKOUT0), apparently this pin is only for the output clock to the Ethernet PHY in RMII mode. I don't think you should use this pin for your camera.

0 Gireesh Hiremath 10 months ago in reply to Bin Liu

Intellectual 405 points

Hi Liu,

Form the clock tool it look independent. any specific reason it bound only to ethernet.

is any alternate to generate clock in MHz from the processor other then PWM?

Regards,

Gireesh Hiremath

0 Hong Guan64 10 months ago in reply to Gireesh Hiremath

TI__Guru 73320 points

Bin is OoO this week. Please expect delayed response till next week.

0 Bin Liu 10 months ago in reply to Gireesh Hiremath

TI__Guru**** 174411 points

Hi Gireesh,

Gireesh Hiremath said:
Form the clock tool it look independent. any specific reason it bound only to ethernet.

I am not an Ethernet expert, and I am routing your query to our device clock expert to comment on how to generate clock to drive external components, then I will help in how to implement it in Linux.

0 Kallikuppa Sreenivasa 10 months ago in reply to Bin Liu

TI__Guru**** 206860 points

Hi Gireesh,

The CLKOUT0 is a 25M or 50M output mostly used for Ethernet interface.

Gireesh Hiremath said:
is any alternate to generate clock in MHz from the processor other then PWM?

I am not sure on the accuracy requirement.

Did you have some target specs for the clock.

Regards,

Sreenivasa

0 Gireesh Hiremath 10 months ago in reply to Kallikuppa Sreenivasa

Intellectual 405 points

Hi,

I am looking for the frequency range from 8-24MHz.

Thanks,

Gireesh

0 Kallikuppa Sreenivasa 10 months ago in reply to Gireesh Hiremath

TI__Guru**** 206860 points

Hello Gireesh

Thank you.

Gireesh Hiremath said:
I am looking for the frequency range from 8-24MHz.

Maybe you could consider using the PRUSS to generate the clock.

I am not sure on the accuracy that can be achieved, this needs to be validated vs requirements.

Regards,

Sreenivasa

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AM623: Enable CLOCKOUT0