I am trying to perform bare metal ADC in stm32 BluePill board using STLink V2 programmer. When debugging I get this error.
"Cannot access Memory (@ 0x08000000, Write, Acc Size: 1024 Byte)
Error while accessing a target resource. Resource perhaps not available or a wrong access was attempted.
*** error 57: illegal address (0x08000000)".
Here is the code....
#include "stm32f10x.h"
void ADC_Init(void);
uint16_t ADC_Read(void);
int main(void) {
//Initialize HSE 8 MHz
//Enable HSE
RCC->CR |= RCC_CR_HSEON;
while(!(RCC->CR & RCC_CR_HSERDY));
//Configure Flash Latency
FLASH->ACR |= FLASH_ACR_LATENCY_2;
//Configure PLL
RCC->CFGR |= RCC_CFGR_PLLSRC_HSE; // RCC->CFGR |= 0x0001 0000;
RCC->CFGR |= RCC_CFGR_PLLMULL9; // RCC->CFGR |= 0x001C 0000;
//Enable PLL
RCC->CR |= RCC_CR_PLLON;
while(!(RCC->CR & RCC_CR_PLLRDY));
//Set PLL as System Clock
RCC->CFGR |= RCC_CFGR_SW_PLL;
while(!(RCC->CFGR & RCC_CFGR_SWS_PLL));
//Configure AHB, APB1, APB2 Prescaler
RCC->CFGR |= RCC_CFGR_HPRE_DIV1; // AHB Prescaler = 1 (72 MHz)
RCC->CFGR |= RCC_CFGR_PPRE1_DIV2; // APB1 Prescaler = 2 (36 MHz max)
RCC->CFGR |= RCC_CFGR_PPRE2_DIV1; // APB2 Prescaler = 1 (72 MHz)
//Update System Core Clock variable
SystemCoreClock = 72000000;
uint16_t adc_value;
ADC_Init(); // Initialize ADC
while (1) {
adc_value = ADC_Read(); // Read ADC value from PA0
}
}
void ADC_Init(void) {
// 1. Enable clock for GPIOA and ADC1
RCC->APB2ENR |= (1 << 2); // Enable GPIOA clock
RCC->APB2ENR |= (1 << 9); // Enable ADC1 clock
// 2. Configure PA0 as analog mode
GPIOA->CRL &= ~(0xF << 0); // Clear bits (Analog mode = 0b0000)
// 3. Configure ADC
ADC1->SMPR2 |= (7 << 0); // Sampling time for channel 0: 239.5 cycles
ADC1->SQR1 &= ~(0xF << 20); // 1 conversion in regular sequence
ADC1->SQR3 |= (0 << 0); // Channel 0 is the first in sequence
// 4. Enable ADC
ADC1->CR2 |= (1 << 0); // Enable ADC
for (int i = 0; i < 10000; i++); // Small delay for stability
// 5. Start ADC Calibration
ADC1->CR2 |= (1 << 2); // Start calibration
while (ADC1->CR2 & (1 << 2)); // Wait until calibration is done
// 6. Enable Continuous Conversion Mode
ADC1->CR2 |= (1 << 1); // Continuous conversion mode
}
uint16_t ADC_Read(void) {
ADC1->CR2 |= (1 << 22); // Start conversion
while (!(ADC1->SR & (1 << 1))); // Wait for conversion to complete
return ADC1->DR; // Read ADC value
}
