wordpress wpposts湖南网站建设seo

---

前言

SPI，想了很久没想明白其DMA或者IT比较好用的方法，可能之后也会写一个
我个人使用场景大数据流不多，如果是大批量数据交互自然是DMA更好用，但考虑到多从机通讯，感觉还是阻塞式更灵活一些，毕竟大部分通讯片选延时1us，但一个数据传进去也就不到1us。
以后有时间改个DMA或者IT升级版

spix = new_SPI_Driver(SPIx_Port, CS_GPIOx, CS_Pin);//完成初始化
RxData = spix->tr16(spix, TxData);//数据传递
spix->cs_l(spix);;//CS拉低
spix->cs_h(spix);;//CS拉搞

SPI的多从机任务可以自己挂CS，并在上层实现数据流读取
上层实现可以参考工程文件参考——ADS1118多从机驱动（base on spi_driver）
需要8位传输的可以自己改

---

CubeMX配置

开了就能用，注意匹配下，数据长度，8bit还是16bit。MSB是先高位还是先低位，以及CPOL与CPHA的设置。NSS硬件片选没什么用，包括从机的NSS，感觉不如外部触发中断。

CS直接开GPIO，根据自己从机数量需求设计

SPI驱动实现

spi_driver.h

/* Define to prevent recursive inclusion -------------------------------------*/
#ifndef __SPI_DRIVER_H
#define __SPI_DRIVER_H
/* =================================================================================
File name:       __SPI_DRIVER_H
Author: Mr.NoFish
===================================================================================*/#ifdef __cplusplus
extern "C" {
#endif/* Includes ------------------------------------------------------------------*/#include "main.h"#include "spi.h"typedef struct SPI_Driver_ SPI_Driver;typedef void (*SPIfptrCS_H)(SPI_Driver*);
typedef void (*SPIfptrCS_L)(SPI_Driver*);
typedef uint16_t (*SPIfptrTranRecv16)(SPI_Driver*, uint16_t);
typedef void (*SPIfptrTran16)(SPI_Driver*, uint16_t);struct SPI_Driver_
{SPI_TypeDef* SPIx;GPIO_TypeDef* CS_GPIOx;uint32_t CS_Pin;uint16_t TxData;uint16_t RxData;SPIfptrCS_H cs_h;SPIfptrCS_L cs_l;SPIfptrTranRecv16 tr16;SPIfptrTran16 tran16;
};SPI_Driver* new_SPI_Driver(SPI_TypeDef* SPIx_Port, GPIO_TypeDef* CS_GPIOx, uint32_t CS_Pin);void spi_chip_select_set(SPI_Driver* const pSPIObj);
void spi_chip_select_reset(SPI_Driver* const pSPIObj);
void spi_transmit_16(SPI_Driver* const pSPIObj, uint16_t TxData);
uint16_t spi_transmit_receive_16(SPI_Driver* const pSPIObj, uint16_t TxData);
#endif

spi_driver.c

/* =================================================================================
File name:       __SPI_DRIVER_C
Author: Mr.NoFish
===================================================================================*/
#include "spi_driver.h"SPI_Driver* new_SPI_Driver(SPI_TypeDef* SPIx_Port, GPIO_TypeDef* CS_GPIOx, uint32_t CS_Pin)
{SPI_Driver* pObj = NULL;uint8_t i = 0;pObj = (SPI_Driver*)malloc(sizeof(SPI_Driver));if (pObj == NULL){printf("WARN: SPI_Driver initialization failed.\r\n");return NULL;}pObj->SPIx = SPIx_Port;pObj->CS_GPIOx = CS_GPIOx;pObj->CS_Pin = CS_Pin;pObj->cs_h = spi_chip_select_set;pObj->cs_l = spi_chip_select_reset;pObj->tran16 = spi_transmit_16;pObj->tr16 = spi_transmit_receive_16;pObj->cs_h(pObj);//LL_SPI_Enable(pObj->SPIx);printf("INFO: SPI_Driver initialization succeeded.\r\n");return pObj;			
}void spi_chip_select_set(SPI_Driver* const pSPIObj)
{LL_GPIO_SetOutputPin(pSPIObj->CS_GPIOx, pSPIObj->CS_Pin);
}void spi_chip_select_reset(SPI_Driver* const pSPIObj)
{LL_GPIO_ResetOutputPin(pSPIObj->CS_GPIOx, pSPIObj->CS_Pin);
}void spi_transmit_16(SPI_Driver* const pSPIObj, uint16_t TxData)
{	pSPIObj->TxData = TxData;while(!LL_SPI_IsActiveFlag_TXE(pSPIObj->SPIx));LL_SPI_TransmitData16(pSPIObj->SPIx, pSPIObj->TxData);
}uint16_t spi_transmit_receive_16(SPI_Driver* const pSPIObj, uint16_t TxData)
{	pSPIObj->TxData = TxData;while(!LL_SPI_IsActiveFlag_TXE(pSPIObj->SPIx));LL_SPI_TransmitData16(pSPIObj->SPIx, pSPIObj->TxData);while(LL_SPI_IsActiveFlag_BSY(pSPIObj->SPIx));while(!LL_SPI_IsActiveFlag_RXNE(pSPIObj->SPIx));pSPIObj->RxData =  LL_SPI_ReceiveData16(pSPIObj->SPIx);return pSPIObj->RxData;
}

---

额外的接口补充

LL_SPI_Enable(SPIx);别忘记自己加一下，但留意别在初始化之前Enable。
SPI每个设备的实现方式都不同，所以需要根据数据手册进一步实现上层设计。
这个库设计用来提供给多从机控制，一些范例的应用可以参考如下文章。
工程文件参考——ADS1118多从机驱动（base on spi_driver）