介绍
SPI总线由开发，是一种，由四个IO口组成：CS、SCLK、MISO、MOSI;通常用于CPU和外设之间进行通信，常见的SPI总线设备有：TFT LCD、QSPI FLASH、时钟模块、IMU等;开发板上集成了两路SPI总线，本次实验将重点介绍RT-Thread系统中SPI BSP驱动的移植过程，以NXP MCXA153为例。
移植流程
以SPI0为例
（1） 在board里边添加相应的外设：配置spi0外设为复位状态、设置GPIO引脚功能
（2） 添加相应的Kconfig开关，用以指示相应的外设开启与关闭（本质是通过宏定义或者条件编译的方式）
（3） 根据SDK_2_14_2_FRDM-MCXA153提供的spi示例工程编写spi总线驱动，需要实现几个关键的函数
SDK_2_14_2_FRDM-MCXA153
https://mcuxpresso.nxp.com/zh/builder?hw=FRDM-MCXA153
rt_hw_spi_init
spi_configure
斯皮克斯
（4） 添加相应的库文件依赖：fsl_lpspi.c、fsl_lpspi_edma.c
引脚对应关系
驱动文件
板。
在函数里加入以下代码 rt_hw_board_init
edma_config_t userConfig = {0};EDMA_GetDefaultConfig(&userConfig);EDMA_Init(DMA0, &userConfig);pin_mux.c
pin_mux.c
在函数里加入以下代码 BOARD_InitPins
RESET_ReleasePeripheralReset(kLPSPI0_RST_SHIFT_RSTn);const port_pin_config_t port1_0_pin56_config = {/* Internal pull-up/down resistor is disabled */kPORT_PullDisable,/* Low internal pull resistor value is selected. */kPORT_LowPullResistor,/* Fast slew rate is configured */kPORT_FastSlewRate,/* Passive input filter is disabled */kPORT_PassiveFilterDisable,/* Open drain output is disabled */kPORT_OpenDrainDisable,/* Low drive strength is configured */kPORT_LowDriveStrength,/* Normal drive strength is configured */kPORT_NormalDriveStrength,/* Pin is configured as LPSPI0_SDO */kPORT_MuxAlt2,/* Digital input enabled */kPORT_InputBufferEnable,/* Digital input is not inverted */kPORT_InputNormal,/* Pin Control Register fields [15:0] are not locked */kPORT_UnlockRegister};/* PORT1_0 (pin 56) is configured as LPSPI0_SDO */PORT_SetPinConfig(PORT1, 0U, &port1_0_pin56_config);const port_pin_config_t port1_1_pin57_config = {/* Internal pull-up/down resistor is disabled */kPORT_PullDisable,/* Low internal pull resistor value is selected. */kPORT_LowPullResistor,/* Fast slew rate is configured */kPORT_FastSlewRate,/* Passive input filter is disabled */kPORT_PassiveFilterDisable,/* Open drain output is disabled */kPORT_OpenDrainDisable,/* Low drive strength is configured */kPORT_LowDriveStrength,/* Normal drive strength is configured */kPORT_NormalDriveStrength,/* Pin is configured as LPSPI0_SCK */kPORT_MuxAlt2,/* Digital input enabled */kPORT_InputBufferEnable,/* Digital input is not inverted */kPORT_InputNormal,/* Pin Control Register fields [15:0] are not locked */kPORT_UnlockRegister};/* PORT1_1 (pin 57) is configured as LPSPI0_SCK */PORT_SetPinConfig(PORT1, 1U, &port1_1_pin57_config);const port_pin_config_t port1_2_pin58_config = {/* Internal pull-up/down resistor is disabled */kPORT_PullDisable,/* Low internal pull resistor value is selected. */kPORT_LowPullResistor,/* Fast slew rate is configured */kPORT_FastSlewRate,/* Passive input filter is disabled */kPORT_PassiveFilterDisable,/* Open drain output is disabled */kPORT_OpenDrainDisable,/* Low drive strength is configured */kPORT_LowDriveStrength,/* Normal drive strength is configured */kPORT_NormalDriveStrength,/* Pin is configured as LPSPI0_SDI */kPORT_MuxAlt2,/* Digital input enabled */kPORT_InputBufferEnable,/* Digital input is not inverted */kPORT_InputNormal,/* Pin Control Register fields [15:0] are not locked */kPORT_UnlockRegister};/* PORT1_2 (pin 58) is configured as LPSPI0_SDI */PORT_SetPinConfig(PORT1, 2U, &port1_2_pin58_config);const port_pin_config_t port1_3_pin59_config = {/* Internal pull-up/down resistor is disabled */kPORT_PullDisable,/* Low internal pull resistor value is selected. */kPORT_LowPullResistor,/* Fast slew rate is configured */kPORT_FastSlewRate,/* Passive input filter is disabled */kPORT_PassiveFilterDisable,/* Open drain output is disabled */kPORT_OpenDrainDisable,/* Low drive strength is configured */kPORT_LowDriveStrength,/* Normal drive strength is configured */kPORT_NormalDriveStrength,/* Pin is configured as LPSPI0_PCS0 */kPORT_MuxAlt2,/* Digital input enabled */kPORT_InputBufferEnable,/* Digital input is not inverted */kPORT_InputNormal,/* Pin Control Register fields [15:0] are not locked */kPORT_UnlockRegister};/* PORT1_3 (pin 59) is configured as LPSPI0_PCS0 */PORT_SetPinConfig(PORT1, 3U, &port1_3_pin59_config);
板/Kconfig
加入SPI0相关配置
menuconfig BSP_USING_SPIconfig BSP_USING_SPIbool "Enable SPI"select RT_USING_SPIdefault yif BSP_USING_SPIconfig BSP_USING_SPI0bool "Enable SPI0"defaultendif
drv_spi.c
spi驱动层修改如下
/** Copyright (c) 2006-2024, RT-Thread Development Team** SPDX-License-Identifier: Apache-2.0** Change Logs:* Date Author Notes* 2024-08-3 hywing The first version for MCXA*/enum{SPI1_INDEX,};struct lpc_spi{struct rt_spi_bus parent;LPSPI_Type *LPSPIx;clock_attach_id_t clock_attach_id;clock_div_name_t clock_div_name;clock_name_t clock_name;DMA_Type *DMAx;uint8_t tx_dma_chl;uint8_t rx_dma_chl;edma_handle_t dma_tx_handle;edma_handle_t dma_rx_handle;dma_request_source_t tx_dma_request;dma_request_source_t rx_dma_request;lpspi_master_edma_handle_t spi_dma_handle;rt_sem_t sem;char *name;};static struct lpc_spi lpc_obj[] ={{.LPSPIx = LPSPI0,.clock_attach_id = kFRO12M_to_LPSPI0,.clock_div_name = kCLOCK_DivLPSPI0,.clock_name = kCLOCK_Fro12M,.tx_dma_request = kDma0RequestLPSPI0Tx,.rx_dma_request = kDma0RequestLPSPI0Rx,.DMAx = DMA0,.tx_dma_chl = 0,.rx_dma_chl = 1,.name = "spi0",},#endif};struct lpc_sw_spi_cs{rt_uint32_t pin;};rt_err_t rt_hw_spi_device_attach(const char *bus_name, const char *device_name, rt_uint32_t pin){rt_err_t ret = RT_EOK;struct rt_spi_device *spi_device = (struct rt_spi_device *)rt_malloc(sizeof(struct rt_spi_device));struct lpc_sw_spi_cs *cs_pin = (struct lpc_sw_spi_cs *)rt_malloc(sizeof(struct lpc_sw_spi_cs));cs_pin->pin = pin;rt_pin_mode(pin, PIN_MODE_OUTPUT);rt_pin_write(pin, PIN_HIGH);ret = rt_spi_bus_attach_device(spi_device, device_name, bus_name, (void *)cs_pin);return ret;}static rt_err_t spi_configure(struct rt_spi_device *device, struct rt_spi_configuration *cfg){rt_err_t ret = RT_EOK;// struct lpc_spi *spi = RT_NULL;// spi = (struct lpc_spi *)(device->bus->parent.user_data);// ret = lpc_spi_init(spi->SPIx, cfg);return ret;}static void LPSPI_MasterUserCallback(LPSPI_Type *base, lpspi_master_edma_handle_t *handle, status_t status, void *userData){struct lpc_spi *spi = (struct lpc_spi *)userData;rt_sem_release(spi->sem);}static rt_ssize_t spixfer(struct rt_spi_device *device, struct rt_spi_message *message){int i;lpspi_transfer_t transfer = {0};RT_ASSERT(device != RT_NULL);RT_ASSERT(device->bus != RT_NULL);RT_ASSERT(device->bus->parent.user_data != RT_NULL);struct lpc_spi *spi = (struct lpc_spi *)(device->bus->parent.user_data);struct lpc_sw_spi_cs *cs = device->parent.user_data;if (message->cs_take){rt_pin_write(cs->pin, PIN_LOW);}transfer.dataSize = message->length;transfer.rxData = (uint8_t *)(message->recv_buf);transfer.txData = (uint8_t *)(message->send_buf);// if(message->length < MAX_DMA_TRANSFER_SIZE)if (0){LPSPI_MasterTransferBlocking(spi->LPSPIx, &transfer);}else{uint32_t block, remain;block = message->length / DMA_MAX_TRANSFER_COUNT;remain = message->length % DMA_MAX_TRANSFER_COUNT;for (i = 0; i < block; i++){transfer.dataSize = DMA_MAX_TRANSFER_COUNT;if (message->recv_buf) transfer.rxData = (uint8_t *)(message->recv_buf + i * DMA_MAX_TRANSFER_COUNT);if (message->send_buf) transfer.txData = (uint8_t *)(message->send_buf + i * DMA_MAX_TRANSFER_COUNT);LPSPI_MasterTransferEDMA(spi->LPSPIx, &spi->spi_dma_handle, &transfer);rt_sem_take(spi->sem, RT_WAITING_FOREVER);}if (remain){transfer.dataSize = remain;if (message->recv_buf) transfer.rxData = (uint8_t *)(message->recv_buf + i * DMA_MAX_TRANSFER_COUNT);if (message->send_buf) transfer.txData = (uint8_t *)(message->send_buf + i * DMA_MAX_TRANSFER_COUNT);LPSPI_MasterTransferEDMA(spi->LPSPIx, &spi->spi_dma_handle, &transfer);rt_sem_take(spi->sem, RT_WAITING_FOREVER);}}if (message->cs_release){rt_pin_write(cs->pin, PIN_HIGH);}return message->length;}static struct rt_spi_ops lpc_spi_ops ={.configure = spi_configure,.xfer = spixfer};int rt_hw_spi_init(void){int i;for (i = 0; i < ARRAY_SIZE(lpc_obj); i++){CLOCK_SetClockDiv(lpc_obj[i].clock_div_name, 1u);CLOCK_AttachClk(lpc_obj[i].clock_attach_id);lpc_obj[i].parent.parent.user_data = &lpc_obj[i];lpc_obj[i].sem = rt_sem_create("sem_spi", 0, RT_IPC_FLAG_FIFO);lpspi_master_config_t masterConfig;LPSPI_MasterGetDefaultConfig(&masterConfig);masterConfig.baudRate = 12 * 1000 * 1000;masterConfig.pcsToSckDelayInNanoSec = 1000000000U / masterConfig.baudRate * 1U;masterConfig.lastSckToPcsDelayInNanoSec = 1000000000U / masterConfig.baudRate * 1U;masterConfig.betweenTransferDelayInNanoSec = 1000000000U / masterConfig.baudRate * 1U;LPSPI_MasterInit(lpc_obj[i].LPSPIx, &masterConfig, CLOCK_GetFreq(lpc_obj[i].clock_name));EDMA_CreateHandle(&lpc_obj[i].dma_tx_handle, lpc_obj[i].DMAx, lpc_obj[i].tx_dma_chl);EDMA_CreateHandle(&lpc_obj[i].dma_rx_handle, lpc_obj[i].DMAx, lpc_obj[i].rx_dma_chl);EDMA_SetChannelMux(lpc_obj[i].DMAx, lpc_obj[i].tx_dma_chl, lpc_obj[i].tx_dma_request);EDMA_SetChannelMux(lpc_obj[i].DMAx, lpc_obj[i].rx_dma_chl, lpc_obj[i].rx_dma_request);LPSPI_MasterTransferCreateHandleEDMA(lpc_obj[i].LPSPIx, &lpc_obj[i].spi_dma_handle, LPSPI_MasterUserCallback, &lpc_obj[i], &lpc_obj[i].dma_rx_handle, &lpc_obj[i].dma_tx_handle);rt_spi_bus_register(&lpc_obj[i].parent, lpc_obj[i].name, &lpc_spi_ops);}return RT_EOK;}INIT_DEVICE_EXPORT(rt_hw_spi_init);
SConscript 脚本
在文件里边加上以下代码 Libraries/MCXA153/SConscript
if GetDepend('BSP_USING_SPI'):src += ['MCXA153/drivers/fsl_lpspi.c']src += ['MCXA153/drivers/fsl_lpspi_edma.c']
测试用例
打开menuconfig使能spi0驱动
短接MISO和MOSI引脚（P1_0和P1_2）进行自发自收测试
测试程序
static struct rt_spi_device *spi_device;static void spi_sample(void){rt_err_t result;struct rt_spi_configuration cfg;uint8_t tx_buf[] = "Hello RT-Thread!";uint8_t rx_buf[sizeof(tx_buf)];rt_base_t cs = 1*32+3;rt_hw_spi_device_attach(SPI_BUS_NAME, SPI_DEV_NAME, cs);/* »ñÈ¡SPIÉ豸 */spi_device = (struct rt_spi_device *)rt_device_find(SPI_DEV_NAME);if (!spi_device){rt_kprintf("can't find %s device!\n", SPI_BUS_NAME);}/* ÅäÖÃSPIÉ豸 */cfg.data_width = 8;cfg.mode = RT_SPI_MASTER | RT_SPI_MODE_0 | RT_SPI_MSB;cfg.max_hz = 12* 1000 * 1000;/* ÉèÖÃSPIÉ豸 */rt_spi_configure(spi_device, &cfg);result = rt_spi_transfer(spi_device, tx_buf, rx_buf, sizeof(tx_buf));if (result == sizeof(tx_buf)){rt_kprintf("Send: %s\n", tx_buf);rt_kprintf("Received: %s\n", rx_buf);}else{rt_kprintf("spi transfer failed! error code: %d\n", result);}}int main(void){spi_sample();return 0;}
运行结果
总结
另外，你也可以安装，通过图形方式配置时钟树、GPIO复用 MCUXpresso Config Tools v16
想要在RT-Thread平台或社区投放内容？或想参与相关直播活动及赛事？RT-Thread已开放对接窗口，请通过邮件与我们取得联系，期待合作！
