I'm trying to transmit a bitmap via USART. The bitmap transmits correctly in HAL. My project is register-based, written from scratch. The issue is that my USART has a speed synchronization problem—meaning:
When my C# terminal is set to 57600 BAUD, it reads one byte correctly, but an additional zero byte is received and written to the buffer index.
At equal speeds (115200 BAUD) for both the MCU and the terminal, it incorrectly reads the bitmap byte, and still receives an extra empty byte in the buffer.
I can't figure out what's wrong. I suspect it might be a misconfigured clock system. My board is Nucleo-F303RE (STM32F3xE). I’d appreciate your help!
void USART2_EXTI26_IRQHandler (void)
{
if(USART2->ISR & USART_ISR_RXNE)
{
dl_znak[ind++] = USART2->RDR;
memcpy(dl_znak+ind,temp,1);
if(++ind >=20) ind=0;
//USART2->RQR |= USART_RQR_RXFRQ;
if (USART2->ISR & USART_ISR_ORE)
{
USART2->ICR |= USART_ICR_ORECF;
}
if (USART2->ISR & USART_ISR_FE)
{
USART2->ICR |= USART_ICR_FECF;
}
if (USART2->ISR & USART_ISR_NE)
{
USART2->ICR |= USART_ICR_NCF;
}
}
}
void config_UART(void)
{
RCC -> AHBENR |= RCC_AHBENR_GPIOAEN;
//PA2_TXAF7
GPIOA -> MODER &= ~(GPIO_MODER_MODER2_0);
GPIOA->MODER |= GPIO_MODER_MODER2_1;
GPIOA->AFR[0] &= ~((0xF << GPIO_AFRL_AFRL2_Pos));
GPIOA->AFR[0] |= (0x7 << GPIO_AFRL_AFRL2_Pos);
//PA3_RXAF7
GPIOA -> MODER &= ~(GPIO_MODER_MODER3_0);
GPIOA->MODER |= GPIO_MODER_MODER3_1;
GPIOA->AFR[0] &= ~((0xF << GPIO_AFRL_AFRL3_Pos));
GPIOA->AFR[0] |= (0x7 << GPIO_AFRL_AFRL3_Pos);
//GPIOA -> OTYPER |= GPIO_OTYPER_OT_3;
//GPIOA->PUPDR |= GPIO_PUPDR_PUPDR3_0;
RCC -> APB1ENR |= RCC_APB1ENR_USART2EN;
RCC -> CFGR |= RCC_CFGR_PPRE1_2;
USART2->BRR = 36000000/115200;
USART2-> CR1 |= USART_CR1_UE | USART_CR1_TE | USART_CR1_RE;
USART2-> CR1 |= USART_CR1_RXNEIE;
NVIC_SetPriority(USART2_IRQn, 0);
NVIC_EnableIRQ(USART2_IRQn);
}
uint8_t data;
uint8_t dl_znak [20];
uint8_t temp[2];
