#include //#include //#include //#include #include "uart.h" static uint8_t tx_buffer[UART_TX_BUFFER_SIZE + 1]; static uint8_t tx_head; static uint8_t tx_tail; static uint8_t rx_buffer[UART_RX_BUFFER_SIZE + 1]; static uint8_t rx_head; static uint8_t rx_tail; void _uart_enable(uint32_t baudrate, bool enable_tx, bool enable_rx) { RCC->APB1ENR |= RCC_APB1ENR_USART2EN; RCC->APB2ENR |= RCC_APB2ENR_IOPAEN; // port A // pins a2 and a3 for usart2 GPIOA->CRL &= (GPIO_CRL_MODE2 | GPIO_CRL_CNF2 | GPIO_CRL_MODE3 | GPIO_CRL_CNF3); GPIOA->CRL |= ((0x1 << GPIO_CRL_MODE2_Pos) | (0x2 << GPIO_CRL_CNF2_Pos) | (0x0 << GPIO_CRL_MODE3_Pos) | (0x1 << GPIO_CRL_CNF3_Pos)); // baudrate uint16_t uartdiv = SystemCoreClock / baudrate; USART2->BRR = (((uartdiv / 16) << USART_BRR_DIV_Mantissa_Pos) | ((uartdiv % 16) << USART_BRR_DIV_Fraction_Pos)); USART2->CR1 |= USART_CR1_UE; if (enable_tx) USART2->CR1 |= USART_CR1_TE; if (enable_rx) USART2->CR1 |= USART_CR1_RE | USART_CR1_RXNEIE; NVIC_EnableIRQ(USART2_IRQn); } void uart_enable(uint32_t baudrate) { _uart_enable(baudrate, true, true); } void uart_enable_tx_only(uint32_t baudrate) { _uart_enable(baudrate, true, false); } void uart_enable_rx_only(uint32_t baudrate) { _uart_enable(baudrate, false, true); } void uart_disable() { NVIC_DisableIRQ(USART2_IRQn); USART2->CR1 &= 0; RCC->APB1ENR &= ~RCC_APB1ENR_USART2EN; GPIOA->CRL &= GPIO_CRL_MODE2 | GPIO_CRL_CNF2 | GPIO_CRL_MODE3 | GPIO_CRL_CNF3; } bool uart_tx_buffer_is_empty() { uint8_t next = (tx_head < UART_TX_BUFFER_SIZE ? tx_head + 1 : 0); return tx_tail != next; } void uart_write(uint8_t * data, uint8_t len) { bool empty = (tx_head == tx_tail); for (int i = 0; i < len; i++) { tx_buffer[tx_head] = data[i]; tx_head = (tx_head < UART_TX_BUFFER_SIZE ? tx_head + 1 : 0); } if (empty) { //USART2->DR = tx_buffer[tx_tail]; USART2->CR1 |= USART_CR1_TXEIE; } } void uart_print(uint8_t * data) { uart_write(data, strlen((char *)data)); } bool uart_data_is_available() { return (rx_head != rx_tail); } uint8_t uart_read() { if (rx_head == rx_tail) return 0; uint8_t c = rx_buffer[rx_tail]; rx_tail = (rx_tail < UART_RX_BUFFER_SIZE ? rx_tail + 1 : 0); return c; } void USART2_IRQHandler(void) { if (USART2->SR & USART_SR_RXNE) { uint8_t next = rx_head + 1; if (next >= UART_RX_BUFFER_SIZE) next = 0; uint8_t v = USART2->DR; if (next != rx_tail) { rx_buffer[rx_head] = v; rx_head = next; } } if (USART2->SR & USART_SR_TXE) { if (tx_head != tx_tail) { USART2->DR = tx_buffer[tx_tail]; tx_tail = (tx_tail < UART_TX_BUFFER_SIZE ? tx_tail + 1 : 0); } else USART2->CR1 &= ~USART_CR1_TXEIE; } }