STM32：使用RS485和多摩川编码器通信

本文主要讲使用STM32F767和绝对式多摩川TS5700N8501编码器通信的流程和注意事项。

TS5700N8501编码器推荐收发电路如下：

 首先使用STM32CubeMX生成RS485驱动部分功能代码，注意该款编码器的波特率是2.5Mbps。

注意使能的GPIO可以使用其他管脚，我们的主控板使用的是PA8。前期可以这么配置。

 配置时钟，这里配置的是48MHz。

 接下来，生成对应的项目工程，MDK-ARM就是生成对应的Keil工程。 

 接下来是接线：注意编码器正确接4根线即可。黑色接地，红色接5V电源。编码器的SD是蓝色，对应接的是控制板上面的管脚。编码器的是蓝黑色，对应接的是控制板上面的SD管脚。

注意编码器要保证5V供电，并且编码器的线比较细要注意保证连接可靠。 测试中遇到供电电压达不到5V，以及黑色接地线接触不好的情况，都会导致无法正常通信。

void MX_UART4_Init(void)
{/* USER CODE BEGIN UART4_Init 0 *//* USER CODE END UART4_Init 0 *//* USER CODE BEGIN UART4_Init 1 *//* USER CODE END UART4_Init 1 */huart4.Instance = UART4;huart4.Init.BaudRate = 2500000;huart4.Init.WordLength = UART_WORDLENGTH_8B;huart4.Init.StopBits = UART_STOPBITS_1;huart4.Init.Parity = UART_PARITY_NONE;huart4.Init.Mode = UART_MODE_TX_RX;huart4.Init.HwFlowCtl = UART_HWCONTROL_NONE;huart4.Init.OverSampling = UART_OVERSAMPLING_16;huart4.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;huart4.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;if (HAL_RS485Ex_Init(&huart4, UART_DE_POLARITY_HIGH, 0, 0) != HAL_OK){Error_Handler();}/* USER CODE BEGIN UART4_Init 2 *///  HAL_UART_Receive_IT(&huart4, rs485RxData, 1);/* USER CODE END UART4_Init 2 */}void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{GPIO_InitTypeDef GPIO_InitStruct = {0};RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};if(uartHandle->Instance==UART4){/* USER CODE BEGIN UART4_MspInit 0 *//* USER CODE END UART4_MspInit 0 *//** Initializes the peripherals clock*/PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_UART4;PeriphClkInitStruct.Uart4ClockSelection = RCC_UART4CLKSOURCE_PCLK1;if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK){Error_Handler();}/* UART4 clock enable */__HAL_RCC_UART4_CLK_ENABLE();__HAL_RCC_GPIOA_CLK_ENABLE();__HAL_RCC_GPIOB_CLK_ENABLE();/**UART4 GPIO ConfigurationPA0/WKUP     ------> UART4_TXPA1     ------> UART4_RXPA8     ------> UART4_DE*/GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1;GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;GPIO_InitStruct.Pull = GPIO_NOPULL;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;GPIO_InitStruct.Alternate = GPIO_AF8_UART4;HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);GPIO_InitStruct.Pin = GPIO_PIN_8;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;GPIO_InitStruct.Pull = GPIO_PULLUP;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;GPIO_InitStruct.Alternate = GPIO_AF8_UART4;HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);/* UART4 DMA Init *//* UART4_RX Init */hdma_uart4_rx.Instance = DMA1_Stream2;hdma_uart4_rx.Init.Channel = DMA_CHANNEL_4;hdma_uart4_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;hdma_uart4_rx.Init.PeriphInc = DMA_PINC_DISABLE;hdma_uart4_rx.Init.MemInc = DMA_MINC_ENABLE;hdma_uart4_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;hdma_uart4_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;hdma_uart4_rx.Init.Mode = DMA_NORMAL;hdma_uart4_rx.Init.Priority = DMA_PRIORITY_LOW;hdma_uart4_rx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;if (HAL_DMA_Init(&hdma_uart4_rx) != HAL_OK){Error_Handler();}__HAL_LINKDMA(uartHandle,hdmarx,hdma_uart4_rx);/* UART4 interrupt Init */HAL_NVIC_SetPriority(UART4_IRQn, 0, 0);HAL_NVIC_EnableIRQ(UART4_IRQn);/* USER CODE BEGIN UART4_MspInit 1 *//* USER CODE END UART4_MspInit 1 */}
}

测试程序： 

void RS485_SendData(uint8_t *data, uint16_t size)
{HAL_GPIO_WritePin(GPIOA, GPIO_PIN_8, GPIO_PIN_SET);HAL_UART_Transmit(&huart4, data, size, 1000);HAL_GPIO_WritePin(GPIOA, GPIO_PIN_8, GPIO_PIN_RESET);
}void RS485_RecvData(uint8_t *data, uint16_t size)
{HAL_UART_Receive(&huart4, data, size, 1000);
}void RS485_Test(void)
{uint8_t Sendbuf[1] = {0x02};uint8_t Recvbuf[10] = {0x00};RS485_SendData(Sendbuf, sizeof(Sendbuf));RS485_RecvData(Recvbuf, 6);for(int i = 0; i < 6; i++){Usart_Printf("%02x", Recvbuf[i]);}Usart_Printf("\n\r");
}

测试程序运行结果： 

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