Timer clock

[_behn4m]

Posted on October 31, 2013 at 15:17

Hi

when I set hclk to 72 for STM32F103 micro the timer doesnt work! I set APB1 pll to devide by 2, but in downt work aftar that alsowhats the problem? #too-vague

[Tesla DeLorean]

Posted on October 31, 2013 at 17:35

To address the earlier version of the question, the clock details can be computed by decomposing the RCC settings, and doing the math. The library function RCC_GetClocksFreq() does this based on HSI_VALUE and HSE_VALUE, the PLL settings, and clock source.

RCC_ClocksTypeDef RCC_ClockFreq;
RCC_GetClocksFreq(&RCC_ClockFreq);
printf(''SYS:%d H:%d, P1:%d, P2:%d, ADC:%d

'',
RCC_ClockFreq.SYSCLK_Frequency,
RCC_ClockFreq.HCLK_Frequency, // AHB
RCC_ClockFreq.PCLK1_Frequency, // APB1
RCC_ClockFreq.PCLK2_Frequency, // APB2
RCC_ClockFreq.ADCCLK_Frequency);

You later question depend on what your code is actually doing, I'm not going to try and guess what you're doing, present a clear example, I'll suggest why it might not be working, or what to change.

[_behn4m]

Posted on October 31, 2013 at 18:24 thank you, I want to use micro on 64 mhz clock, but when I set it like folowing, it doesnt work, I think it may be because of APB over clock?!

void config_TIM2()
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
/* TIM2 clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
/* Time base configuration */
TIM_TimeBaseInitStructure.TIM_Period = 65000 - 1; // 100 KHz down to 10 Hz (100 ms)
TIM_TimeBaseInitStructure.TIM_Prescaler = 64000 - 1; // 36 MHz Clock down to 100 KHz (adjust per your clock)
TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
/* Initialize TIM2 */
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure);
/* TIM2 enable counter */
TIM_Cmd(TIM2, DISABLE);
}
void delay_ms(u16 ms)
{
config_TIM2();
TIM_Cmd(TIM2, ENABLE);
while ((TIM2->CNT) < ms );
TIM_Cmd(TIM2, DISABLE);
}
void main(void)
{
RCC_HCLKConfig(RCC_SYSCLK_Div1);// HCLK = 64 MHz, AHB
RCC_PCLK1Config(RCC_HCLK_Div2); // APB1 = 32 MHz
RCC_PCLK2Config(RCC_HCLK_Div1); // APB2 = 64 MHz 
/* PLLCLK = 4MHz * 16 = 64 MHz */
RCC_PLLConfig(RCC_PLLSource_HSI_Div2, RCC_PLLMul_16);
/* Enable PLL */
RCC_PLLCmd(ENABLE);
/* Wait till PLL is ready */
while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);
/* Select PLL as system clock source */
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
/* Wait till PLL is used as system clock source */
while(RCC_GetSYSCLKSource() != 0x08);
//RCC_HCLKConfig(RCC_SYSCLK_Div2);
//RCC_PCLK1Config(RCC_HCLK_Div8);
config_TIM2();
config_IO();
GPIO_SetBits(GPIOA, GPIO_Pin_1);
while (1)
{
delay_ms(10000);
GPIO_ResetBits(GPIOA, GPIO_Pin_1);
delay_ms(10000);
GPIO_SetBits(GPIOA, GPIO_Pin_1); 
}
}

[Tesla DeLorean]

Posted on October 31, 2013 at 18:33

Doesn't work how? Does the clock tick, does it get stuck in a loop, does the GPIO not change.

You must be using an older version of the library, v3.5.0 should have the PLL setting code in SystemInit() in system_stm32f1xx.c, which is called prior to main(). What tools and library are you using?

[_behn4m]

Posted on October 31, 2013 at 18:39

version is @version V3.5.0

no blink, LED is off. I dont know about clock tick, I dont have any debug toolI use KEIL v4.7what should I do about  SystemInit()? 

[Tesla DeLorean]

Posted on October 31, 2013 at 18:55

I don't see the code initializing the GPIO/LED, check that is correct.

Try setting the LED on/off prior to setting the clocks (ie whilst still running at 8 MHz). Toggle the GPIO in a tight loop, no delays, observe with a scope. Modify the clock set up code in system_stm32f1xx.c to match your HSI clock source and PLL settings. Use the project template from the firmware library. Get a debugger, otherwise you're going to spend forever pondering what is not working and why.

[_behn4m]

Posted on October 31, 2013 at 19:08

ok, SOLVED

I don't know why! but flash latency should be set :

RCC_HCLKConfig(RCC_SYSCLK_Div1);// HCLK = 64 MHz, AHB
RCC_PCLK1Config(RCC_HCLK_Div2); // APB1 = 32 MHz
RCC_PCLK2Config(RCC_HCLK_Div1); // APB2 = 64 MHz 
/* set up FLASH */
FLASH_SetLatency(FLASH_Latency_2);
FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);
/* PLLCLK = 4MHz * 16 = 64 MHz */
RCC_PLLConfig(RCC_PLLSource_HSI_Div2, RCC_PLLMul_16);
/* Enable PLL */
RCC_PLLCmd(ENABLE);
/* Wait till PLL is ready */
while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);
/* Select PLL as system clock source */
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
/* Wait till PLL is used as system clock source */
while(RCC_GetSYSCLKSource() != 0x08);

So I still don't know how I should know points like this before start programming!? there is no good documentation about libraries? also I need more information for when ever I should wait on e flag for a while?

[_behn4m]

Posted on October 31, 2013 at 19:09

it blinks when I set on up to RCC_PLLMul_14, but when 15 or 16 it stucks!

I use the the template project! every thing works correct on 8 MHZI use my custom PCB and no debug pin is available on it tank you for your helps, I'm going work on it

[Tesla DeLorean]

Posted on October 31, 2013 at 22:29

If you want to understand how the part functions, then you'll need to digest the Reference Manual, Data Manual, and the Cortex-M3 TRM. There is also a presumption of some general familiarity with micro-processors/controllers.

The firmware library comes with many examples, and sample code. There should also be a .CHM help file describing the functions, but they are basically masking the data in the RM The code in system_stm32f1xx.c should have an example of how the clocks are set up. If you use the startup_stm32f1xx.s, it calls SystemInit() The flash operates at about 24 MHz, for each increment of 24 MHz you need to insert an additional wait state.