clock division

[manoritesameer]

Posted on October 02, 2014 at 21:51

Hello,

       I am having hard time to figure this out. in the data sheet it is mentioned that the STM32F407 works at a maximum clock of 168 Mhz, but using any module timer, PWM or any other the clock is divided by 2 or more. so technically the clock is just 84 Mhz .

Is this consistent with all the micro controllers out there or its just with arm. Also it there a way to increase this clock rate, I mean the system speed.

thansks 

#stm32

[Tesla DeLorean]

Posted on October 02, 2014 at 22:24

I am having hard time to figure this out. in the data sheet it is mentioned that the STM32F407 works at a maximum clock of 168 Mhz, but using any module timer, PWM or any other the clock is divided by 2 or more. so technically the clock is just 84 Mhz .

 

 

Is this consistent with all the micro controllers out there or its just with arm. Also it there a way to increase this clock rate, I mean the system speed.

Getting high rate clocks out of the part requires a lot of energy, the pin drivers are rated at about 90 MHz, and then you'd have to consider very carefully what you were driving, and over what distance.

Internally the 168-180 MHz clock domain is in 1.2V portions of the die.

It's not just ARM, any counting element using flip-flops is apt to divide the clock in two. The other alternative is to clock on both edges of the clock.

There are plenty of micros out there that clock in the 400-500 MHz region, on finer geometries, and using non Cortex-Mx architectures. There are also DDS parts clocking internally at GHz rates.