ChibiOS Free Embedded RTOS

i have some question about the pwm driver...i draw a picture to describe this question ,but i don't know how to post it to this .....
https://drive.google.com/file/d/1r3nk97 ... sp=sharing
i use the stm32f103,maybe i need to change the pwm config to deal this problem?

You need to use the PWM Period callback.
It happens at the rising edge of the PWM.