S12 / MagniV MicrocontrollersのトピックRe: S12ZVLA128 Timer module 1ms interrupt

S12ZVLA128 Timer module 1ms interrupt

oceansea — Tue, 09 Jul 2019 08:56:06 GMT

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

Re: S12ZVLA128 Timer module 1ms interrupt

kef2 — Wed, 10 Jul 2019 14:26:42 GMT

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.

Re: S12ZVLA128 Timer module 1ms interrupt

oceansea — Thu, 11 Jul 2019 00:55:26 GMT

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

Re: S12ZVLA128 Timer module 1ms interrupt

kef2 — Thu, 11 Jul 2019 06:30:03 GMT

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.

Re: S12ZVLA128 Timer module 1ms interrupt

danielmartynek — Thu, 11 Jul 2019 07:18:38 GMT

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

Re: S12ZVLA128 Timer module 1ms interrupt

oceansea — Wed, 17 Jul 2019 02:50:26 GMT

thank you my friend ,i have solve the problem.

Re: S12ZVLA128 Timer module 1ms interrupt

oceansea — Wed, 17 Jul 2019 02:51:32 GMT

thank you my friend ,i have solve the problem.