MCU can't be flashed anymore
Hi everyone,
First I am sorry for the uneducated rest of this text and badly written code.
I am currently playing around with a stm32f4 chip. I am using Platform IO CMSIS and a cheap stlink v2 to program the chip. I was trying to get PWM working when the chip wouldn't connect anymore.
I was trying to do this by using the TIM1 peripheral which didn't work and then switched to the TIM3. Unfortunately I am not sure when the chip stopped to respond. I also coded my own clock config which worked fine the first 100 flashes or so.
I have heart that bad clock config can "brick" the chip but since it worked and then didn't even tough I didn't touch the clock code anymore I am confused.
Here is my clock config:
#include "clock_config.h"
/**
* Configures the stm32 to use the internal 16Mhz clock
*/
void configure_clock(){
// Reset the flash 'Access Control Register'
// set wait-state to 1
// enable prefetch buffer
FLASH->ACR &= ~(FLASH_ACR_LATENCY_Msk | FLASH_ACR_PRFTEN_Msk);
FLASH->ACR |= (FLASH_ACR_LATENCY | FLASH_ACR_PRFTEN);
// activate the internal 16 MHz clock
RCC->CR |= RCC_CR_HSION;
// wait for the clock to become stable
while (!(RCC->CR & RCC_CR_HSIRDY)){}
// AHB and APB clocks are not configured but should be just not divided so run on 16Mhz as well
}
And here is the rest of my code:
uint16_t arr_from_freq(uint16_t freq){
return F_CLK/(freq*(TIM3->PSC+1)) - 1;
}
int main(){
// Enable GPIO port A and TIM3 peripherals
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN;
RCC->APB1ENR |= RCC_APB1ENR_TIM3EN;
// Set the mode of GPIOA pin 6 to alternate function mode 2
GPIOA->MODER = GPIO_MODER_MODER6_1;
GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR6;
GPIOA->AFR[0] |= 0b0010 << (7*4);
// Disable the timer before setting the prescaler and overflow values
TIM3->CR1 &= ~TIM_CR1_CEN;
// Set the prescaler and overflow values
TIM3->PSC = 0;
TIM3->ARR = arr_from_freq(pwm_frequency);
TIM3->CCR1 = 0;
// Set the PWM mode 1
TIM3->CCMR1 |= TIM_CCMR1_OC1M_2 | TIM_CCMR1_OC1M_1;
TIM3->CCMR1 |= TIM_CCMR1_OC1PE;
// Set the output polarity to active high
TIM3->CCER |= TIM_CCER_CC1E;
// Enable the main output
TIM3->BDTR |= TIM_BDTR_MOE;
// Enable auto reload preload
// configures a buffer register for ARR and CCR1 so that those values
// do not get changed while the timer is still counting
TIM3->CR1 |= TIM_CR1_ARPE;
// Enable the timer
// Set the center-aligned mode
TIM3->CR1 |= TIM_CR1_CMS_0 | TIM_CR1_CEN;
uint16_t duty = arr_from_freq(pwm_frequency)/2;
for (;;){
TIM3->CCR1 = duty;
}
return 0;
}
Thanks in advance to anyone willing to help.