ADC and Watchdog Timer on MSP430G2231

George Hug

I can't find it now, but I've read somewhere in the TI literature that if the WDT is not to be used as the clock for ADC, it must be turned off. Is that correct?

I'm using the WDT as an interval timer, clocked by the 8 MHz SMCLK divided by 32768, and I don't want to stop it. But about 4 times a second, I want to do an ADC clocked by something much faster. Is there a problem doing that? Seems like there shouldn't be.

over 9 years ago

0 Dennis Eichmann over 9 years ago

Guru 74080 points

Hi George!

The watchdog has nothing to do with the ADC. Of course you can use it as an interval timer and then trigger the ADC in some way, but the watchdog timer is the watchdog timer and the ADC is the ADC.

For me it seems as if you mix things up a little bit. Are you sure you are using the WDT or is it just the real timer module in the MSP? A divider of 32768 is new to me, too. Maybe you show your code so we can see what we are talking about.

Dennis

0 Leo Bosch over 9 years ago in reply to Dennis Eichmann

Guru 23000 points

Dennis Eichmann said:
A divider of 32768 is new to me

Dennis, the Watchdog timer can divide the clock source by some fixed divider values, one of them – and is also the maximum- is 32768.

0 Dennis Eichmann over 9 years ago in reply to Leo Bosch

Guru 74080 points

Interesting, didn't know that. As I said: New to me :-) Thanks for the update!

0 Jens-Michael Gross over 9 years ago

Guru 227245 points

The WDT divides SMCLK internally, for all other modules, SMCLK remains 4MHz.
The ADC doesn't run with much higher frequency than that. 5-6MHz (see datasheet) are the maximum anyway.

**Attention** This is a public forum

MSP low-power microcontrollers

MSP low-power microcontroller forum

ADC and Watchdog Timer on MSP430G2231