How can l read system clock in MPC5644A and MPC5745R?

[jinshuaixu]

Hello,

Now l meet a question,when l develop my product use MPC5644A chip,l can not find the way that to read system clock.The same question happen in MPC5745R chip.

Very thank you if you can reply me and tell me the way t0 resolve it.

[petervlna · Accepted solution]

Hello,

Ok, you didn't share the package before so I answered generally.

I am not sure here if you want to read its settings (how the sys clk is configured) or if it is in configured range all the time.

For SPC5644A you can use :

For SPC5745R:

In mode entry module you can read sys clk:

Its configuration can be read out from Clock Generation Module (MC_CGM) registers. Based on the SYS_CLK source.

For more details refer to reference manual.

Best regards,

Peter

[petervlna]

Hello,

Not sure what you mean, But you can

1. read it at CLKOUT pin

Or via SW at

For more details please refer to reference manual Chapter 17 Frequency-modulated phase locked loop (FMPLL)

Best regards,

Peter

[jinshuaixu]

Hello，petervlna:

Thank you for you response first,CLKOUT function in Mpc5644A 176PIN maybe is not exist.you can see the introduce from below picture.

you remind me that can read system clock from SW register, could you give me some sample ?thank you.

Xu Jinshuai

3/10/2023