Here i am trying to generate a 24 bit PWM signal using timer 2 in STM32F401RE controller. I followed as per the steps only but still i not getting any output waveform on my logic analyzer. Please share your suggestions.
void tim_init();
GPIO_HANDLE pwm;
uint8_t green[24]={13,13,13,13,13,13,13,13, 7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7}; // Green
void dma_init()
{
// Enable DMA1
DMA1_CLK_EN;
// Disable the Stream
DMA1->DMA_S5CR = 0;
// Wait till DMA stream is disabled
while(DMA1->DMA_S5CR & 1);
// Clear Error Flags
// Direct Mode Error
DMA1->DMA_HIFCR |= (1 << 8);
// Transfer Error Flag
DMA1->DMA_HIFCR |= (1 << 9);
// Transfer Complete Flag
DMA1->DMA_HIFCR |= (1 << 11);
// Select the channel 3
DMA1->DMA_S5CR |= (3 << 25);
// Memory Increment
DMA1->DMA_S5CR |= (1 << 10);
// Transfer Direction Mem to Peri
DMA1->DMA_S5CR |= (1 << 6);
// Transfer Length
DMA1->DMA_S5NDTR = (uint16_t)24;
// Peripheral Address
DMA1->DMA_S5PAR = (uint32_t)(&TIM2->TIMx_CCR1);
// Memory Address
DMA1->DMA_S5M0AR = (uint32_t)&green;
// Enable DMA Stream
DMA1->DMA_S5CR |= (1 << 0);
// Enable the timer
TIM2->TIMx_CR1 |= (1 << 0);
}
void delay(uint16_t x)
{
TIM4->TIMx_ARR = x;
TIM4->TIMx_CNT = 0;
TIM4->TIMx_CR1 |= (1 << 0);
while(TIM4->TIMx_CNT < x);
}
int main()
{
GPIOA_PCLK_EN;
// PWM Alternate Functionality
pwm.pGPIOx = GPIOA;
pwm.GPIO_PinConfig.GPIO_PinMode = GPIO_MODE_AF;
pwm.GPIO_PinConfig.GPIO_PinAltFunMode = 1;
pwm.GPIO_PinConfig.GPIO_PinNumber = 0;
GPIO_Init(&pwm);
tim_init();
while(1)
{
dma_init();
delay(1000);
}
}
void tim_init()
{
// Enable clock for timer 2
TIM2_EN;
// Pre-scaler is 1 to generate 800 KHz freq using 16MHz HSI
TIM2->TIMx_PSC = 1 - 1;
// Store the count in ARR
TIM2->TIMx_ARR = 20-1; // 1.25 micro seconds
// Reset Counter
TIM2->TIMx_CNT = 0;
// Enable OC1PE bit and OC1M bit
TIM2->TIMx_CCMR1 |= ((6 << 4) | (1 << 3));
// Enable Capture Compare 1 DMA request // Enable Update DMA request enable // Enable Trigger DMA request
TIM2->TIMx_DIER |= ((1 << 9)|(1 << 8)|(1 << 14));
// Timer CCER bit enable
TIM2->TIMx_CCER |= (1<<0);
// Timer for Delay generation
TIM4_EN;
TIM4->TIMx_PSC = 16000-1;
}
