2384620_en-US

Yes

The S32K144 chip has a clock configuration issue; the timing period changes after the clock is modified.

I encountered the following problem during the development of S32K144:

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The initialization timer's interrupt overflow period should be 1 second.
The premise is that my clock configuration is 8MHz.

Ni__1-1782182016343.pngNi__2-1782182026827.png

However, after I changed the clock to a 20M clock...

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I discovered that my timer overflow period is no longer 1 second, but has become 400 milliseconds.
However, my timer clock selection is still set to the 8MHz internal clock.

PCC->PCCn[PCC_FTM1_INDEX] |= PCC_PCCn_PCS(0x01) /* Clock src=1, 8 MHz SIRCDIV1_CLK */
| PCC_PCCn_CGC_MASK; /* Enable clock for FTM regs */

I'm not sure what configuration issue is causing this problem.

Re: S32K144芯片的时钟配置问题，更改时钟后定时周期出现变化

Hi

建议看一下S32K1 RM的Table 27-9. Peripheral module clocking (continued)，FTM具体选择哪个时钟源需要查看FTMn_SC[CLKS]和29.6.17 PCC FTM1 Register (PCC_FTM1)的PCS位。

Table 27-9. Peripheral module clocking FTM.png

你用Processor Expert生成配置，又用baremetal方式直接操作寄存器。我不确定是否是因为调用了SDK里的API导致和你的baremetal程序冲突了。建议debug情况下直接检查上述两个寄存器。

顺便提一句，baremetal直接操作寄存器的话建议参考S32K144_Project_FTM例程，如果想用ProcessorExpert 搭配SDK的API则建议参考ftm_periodic_interrupt_s32k144例程。

Best Regards,
Robin