Looking for TIM2 multiplier

andy239955_st · ‎2008-01-04

Posted on January 04, 2008 at 10:06

andy239955_st · ‎2011-05-17

Posted on May 17, 2011 at 12:20

Hi Niklas,

That explains everything :) Thanks very much for pointing that out.

Cheers.

Andy.

andy239955_st · ‎2011-05-17

Posted on May 17, 2011 at 12:20

Hi Folks,

I'm trying to set up timer2 on my STM32F103 project and things aren't going quite to plan.

Looking at the clock tree on page 48 of the datasheet I can see that the output of the APB1 prescaler passes into the ''TIM2, 3, 4 x1,2 Multiplier''.

I can't find any mention of this multiplier anywhere else in the datasheet and as my clock is running too fast I think it may be responsible.

Does anyone know where I can find this and the register that controls it?

Thanks.

Andy.

niklas · ‎2011-05-17

Posted on May 17, 2011 at 12:20

Hi Andy,

It took me a while to find that multiplier as well.

Looking at the top of page 50 (RM0008, rev2), just before sction 4.2.1, it says:

''The timer clock frequencies are twice the frequency of the APB domain which they are connected to. Nevertheless, if the APB prescaler is 1, the clock frequency of the timer is the same as the frequency of the APB domain which it is connected to.''

The TIM2CLK is PCLK1*2, but never higher than HCLK.

/Niklas