AM5718: Frequency calibration for 20M crystal oscillator

Hello Jiazhe,

What software are you using? Linux perhaps?

Some methods are using NTP.

-Josue

Linux

FUNC_32K_CLK=SYS_CLK1/610

20000000/610=32786.885246Hz

For the Device Tree.

sys clk32 pseudo ck {
#clock-cells =<0x00>;
compatible ="fixed-factor-clock";
clocks =<0x01>;
clock-div = <0x262>;
phandle = <0x0d>;
};

as I know,FUNC_32K_CLK > 32768,so the system clock is run faster than it should be,I want to configure my system clock to be as accurate as possible,How should I set it up

If I am using a QNX system, do you know where I should make changes to resolve this issue?

Josue,

After following the instructions in [FAQ] AM5718: AM57xx Clock Drift Issue, I found that it affected my internet connection. I am using Linux 5.10  SDK 8.02.01.00. I'm not sure if this method is applicable to my version.

best, 

Jiazhe

Jiazhe,

Yes, the patches were done on kernel 6.1 as mentioned in the FAQ. you probably have a conflict that you need to resolve.

SDK 8.2's support window has expired and it is now in as-is state. The FAQ shows you an example of how to achieve less drift, which answers your query:

Jiazhe Li said:

FUNC_32K_CLK > 32768,so the system clock is run faster than it should be,I want to configure my system clock to be as accurate as possible,How should I set it up

Best,

-Josue

Hi，Josue

       I got some information from the AM571x TRM, the internal RTC can use an external 32768Hz crystal. I want to confirm that if the clock from the external 32768Hz crystal can be used by other internal modules. I think that the external 32768Hz crystal is used ONLY by the internal RTC, and can NOT be used by any other modules. Am I right? But someone told me that the clock from the external 32768Hz crystal can be used by other module.

       I read the AM571x TRM and datasheet, but get nothing I want. So, I want to get the right answer.

Best,

Jiazhe

Hello Jiazhe,

Jiazhe Li said:

the external 32768Hz crystal is used ONLY by the internal RTC, and can NOT be used by any other modules

I infer the same thing from the TRM but I will reassign this thread to our HW engineers for confirmation.

Secondly, this question diverts enough from the original question that it would be helpful for our E2E findability for you to make this a new question by clicking above on the + Ask a related question.

-Josue