UART
The Universal Asynchronous Receiver Transmitter (UART) module provides a flexible way to perform full-duplex data exchange with external devices requiring industry-standard NRZ asynchronous serial data format. The UART offers a very wide range of baud rates using a programmable baud rate generator. It supports modem operations (CTS/RTS) and DMA (Direct Memory Access) for high-speed communication.
UART Key Features
Configurable 16 or 8 oversampling methods to provide flexibility between speed and clock tolerance.
Widely programmable transmit and receive baud rates up to 3 Mbit/s
Programmable data word length (7, 8 or 9 bits)
Configurable stop bits (1 or 2 stop bits)
Continuous communication using DMA
Communication control/error detection flags
Parity control: transmit parity bit, check parity of received data bytes
Note that the UART FIFO size in SiFli chipsets is 1 byte. It is strongly recommended to use DMA in the RX direction.
Using UART
The following example shows UART TX and RX. For UART DMA usage, please refer to drv_usart.c in the RTOS Sifli BSP folder (rtos/rtthread/bsp/sifli/drivers) as an example.
{
#include "bf0_hal.h"
void USART4_IRQHandler(void) // Implement for UART interrupt handler
{
if ((__HAL_UART_GET_FLAG(&(uart->handle), UART_FLAG_RXNE) != RESET) &&
(__HAL_UART_GET_IT_SOURCE(&(uart->handle), UART_IT_RXNE) != RESET))
printf("Get UART %c", __HAL_UART_GETC(&(uart->handle)));
}
...
UART_HandleTypeDef UartHandle;
UartHandle.Instance = USART4;
UartHandle.Init.BaudRate = 1000000;
UartHandle.Init.WordLength = UART_WORDLENGTH_8B;
UartHandle.Init.StopBits = UART_STOPBITS_1;
UartHandle.Init.Parity = UART_PARITY_ODD;
UartHandle.Init.HwFlowCtl = UART_HWCONTROL_NONE;
UartHandle.Init.Mode = UART_MODE_TX_RX;
UartHandle.Init.OverSampling = UART_OVERSAMPLING_16;
if (UartHandle.Init.Parity)
UartHandle.Init.WordLength = UART_WORDLENGTH_9B; // If parity is odd/even, parity should +1
if (HAL_UART_Init(&UartHandle) == HAL_OK) // Initialize UART
{
HAL_UART_Transmit(&UartHandle, "UART Tx example", 15, 0xFFFF); // UART TX
}
NVIC_EnableIRQ(USART4_IRQn); // Enable UART interrupt
__HAL_UART_ENABLE_IT(&(uart->handle), UART_IT_RXNE); // Enable UART RXNE interrupt source.
// Type on other side of UART will trigger UART interrupt for RX.
...
}