S12 / MagniV MicrocontrollersのトピックRe: Clearing TCNT counter to 0

Clearing TCNT counter to 0

Pallavi — Mon, 16 Feb 2026 06:01:41 GMT

Hello Everyone. I need a support to clear TCNT register to 0.

While control comes from boot to App, I need clear TCNT register to 0.

I aware that , TNCT can't be cleared in normal mode. From google, i understand that below 2 are methods available.

Method 1: Using Timer Channel 7 (Hardware Reset) : As I want to clear TCNT only once, I didn’t try this method.

Method 2: System/Module Reset (Force Clear) : I have tried this way .

Clear the TEN bit (Timer Enable) in the TSCR1 (Timer System Control Register 1) to turn off the timer. TSCR1_TEN =0;
Set the TEN bit to re-enable it (TSCR1_TEN =1 ;). This should clear TCNT to 0000.

But this method is not working . Please help me out to solve this issue

danielmartynek — Tue, 17 Feb 2026 11:32:47 GMT

Can you please specify the MCU?

Pallavi — Tue, 24 Feb 2026 13:11:29 GMT

Hello ,

I am using MC9S12ZVLA128

danielmartynek — Thu, 26 Feb 2026 14:28:19 GMT

Unfortunately, there is no option to clear the counter on S12ZVLA.

However, why would you need to clear it? What would be the use case?

BR, Daniel

Pallavi — Fri, 27 Feb 2026 06:46:59 GMT

TCNT has incremented in bootloader before control comes to app. In app, i am calling 10ms, task depending onTCNTcount.

As of now I am reading the current count and calling 10ms task from that count value.

Instead of that I thought of clearing TCNT when control comes to app and then schedule 10ms task.

danielmartynek — Fri, 27 Feb 2026 08:29:00 GMT

You are doing it correctly, this is how output compare is updated.

BR, Daniel

Pallavi — Mon, 02 Mar 2026 05:37:37 GMT

Thank you Daniel for confirming.