S12ZVLA128 Timer module 1ms interrupt

[oceansea]

hello,

i use the S12ZVLA128 MCU development a product ,now i have a problem.

i set the internal-bus-clock 24MHZ,  CAN bit-rate is 500Kbps.   then i want use the Timer module(TIM16B6CV3)，i need a 1ms interrupt ,because i want do someting in the  TIM_interrupt_ISR (for example :switch I/O every 1ms, send a CAN message every 10ms) .  i disable  the precision-timer ,the prescaler maxvalue is bus-clock/128   ,so the Timer frequency is 24000000/128=187500,period is 5.3us  ;this can't meet my requirements ,so,what should i do ? thank you very much!

           haiyang 

           2019-0709

[oceansea]

hello Edward Karpicz，thanks reply.

but i can't understand about:perfectly fit timer period 24E6/(1/0.001) < 2^16?

could you detailed description about this?

thank you very 

haiyang

[danielmartynek]

Hello,

You can refer to this example:

Example S12ZVL ADC0 triggered by TIM0 OC updates PWM duty cycle 

The OC is 25ms in this case.

BR, Daniel

[oceansea]

thank you my friend  ,i have solve the problem.

[kef2]

I meant that you need 1ms interrupt period, right? 1ms perfectly fits into 16bits timer running at 24MHz.

24M / (1/1ms) = 24000, which is much less than you have in 16bits timer, which has pow(2, 16)=65536 of timer ticks overflow period. So just go with this, you don't need prescaler.

[oceansea]

thank you my friend  ,i have solve the problem.

[kef2]

Timer prescaler just increases jitter for input capture function and reduces resolution for output compare function. If you need 1ms interrupt then you perfectly fit timer period 24E6/(1/0.001) < 2^16.