full speed micro

Posted on October 05, 2010 at 16:35

It is documented to be 24 MHz, you need to configure the PLL, and you can use the AHB/APB1/APB2 with no scaling (ie at 24 MHz). The flash will also run at this speed without wait states.

The PLL would be set to (HSE / 2) * 6

If you are using the standard library you can select the speed in system_stm32f10x.c by changing a #define, or program it yourself, either way review the code in the ST firmware library (at the address printed on the board) to see how to configure the clocks.

Posted on October 06, 2010 at 08:10

thanks for the replay .

i used this configuration:

 RCC->APB2ENR |=0x14;

 RCC->CR = (uint32_t)0x00000000;

 RCC->CFGR=0x4000005;

 RCC->CR=0x1090000;

but still i cant get any higher then 8Mhz.

why?

Posted on October 06, 2010 at 10:18

As far as I can see from your magic numbers you don't select the PLL as system clock. You can try something like this (it seems to work but I don't know if it's the correct way to do it)

    //// Configure system clock PLL*3 driven by  external high speed

    //// oscillator (8 MHz crystall) 24MHz

    // Turn on high speed external oscillator

    RCC->CR |= RCC_CR_HSEON;

    // Wait until it's ready

    while ((RCC->CR & RCC_CR_HSERDY) == 0)

        ;

    // Select PREDIV1 as PLL source and sett PLL mul to 3 (set bit 0)

    // for 8*3 = 24 MHz

    RCC->CFGR |= RCC_CFGR_PLLSRC | RCC_CFGR_PLLMULL_0;

    // Start PLL

    RCC->CR |= RCC_CR_PLLON;

    // Wait until it's ready

    while ((RCC->CR & RCC_CR_PLLRDY) == 0)

        ;

    // Select PLL as system clock

    RCC->CFGR |= RCC_CFGR_SW_PLL;

    // Here we can check if PLL is used, and maybe disable HSI

    // Disable HSI

    RCC->CR &= ~RCC_CR_HSION;

(Is there some kind of code tags one can use?)

Posted on October 06, 2010 at 10:30

thank you very much it works :)