1 NRF52832SPI主机的功能描述

nRF52832SPIM的主要特征

3个SPI实例

支持SPI的模式0到模式3

支持DMA

Individual selection of IO pin for each SPI signal

注意：SPI主控制器不支持直接片选，因此SPI主机的CPU必须使用可用的GPIO来实现对从机的片选控制。另外，SPI可与和它具有相同ID的其他外设共享寄存器和其他一些资源。配置和使用SPI之前必须关闭与它有相同ID的外设。关闭与SPI有相同ID的外设，不会复位与SPI共享的寄存器。因此为了确保SPI正常运行，必须配置相关的SPI寄存器。

2 软件设计

2.1

#define NRF_DRV_SPI_DEFAULT_CONFIG                           \{                                                            \    .sck_pin      = NRF_DRV_SPI_PIN_NOT_USED,                \  //SCK时钟引脚    .mosi_pin     = NRF_DRV_SPI_PIN_NOT_USED,                \  //MOSI引脚    .miso_pin     = NRF_DRV_SPI_PIN_NOT_USED,                \  //MISO引脚    .ss_pin       = NRF_DRV_SPI_PIN_NOT_USED,                \  //SS引脚    .irq_priority = SPI_DEFAULT_CONFIG_IRQ_PRIORITY,         \  //中断优先级    .orc          = 0xFF,                                    \    .frequency    = NRF_DRV_SPI_FREQ_4M,                     \  //SPI通信的速率    .mode         = NRF_DRV_SPI_MODE_0,                      \  //SPI的工作模式    .bit_order    = NRF_DRV_SPI_BIT_ORDER_MSB_FIRST,         \  //MSB先行或LSB先行}

NRF_DRV_SPI_DEFAULT_CONFIG宏用来配置SPI的基本信息。其中SPI_DEFAULT_CONFIG_IRQ_PRIORITY用来配置SPI的中断优先级，在写程序时要注意合理的配置中断优先级，防止两个外设的中断优先级相同，在nRF52832中，中断号为0代表中断优先级最高。

2.2 代码

#include "nrf_drv_spi.h"#include "app_util_platform.h"#include "nrf_gpio.h"#include "nrf_delay.h"#include "boards.h"#include "app_error.h"#include 
    
     #include "nrf_log.h"#include "nrf_log_ctrl.h"#include "nrf_log_default_backends.h"#define SPI_INSTANCE  0 /**< SPI instance index. */static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);  /**< SPI instance. */static volatile bool spi_xfer_done;  /**< Flag used to indicate that SPI instance completed the transfer. *///#define TEST_STRING "Nordic"//static uint8_t       m_tx_buf[] = TEST_STRING;           /**< TX buffer. *///static uint8_t       m_rx_buf[sizeof(TEST_STRING) + 1];    /**< RX buffer. *///static const uint8_t m_length = sizeof(m_tx_buf);        /**< Transfer length. */#define W25X_WriteEnable 0x06#define W25X_JedecDeviceID 0X9F#define W25X_ReadStatusReg 0x05#define W25X_SectorErase 0xD8#define W25X_PageProgram 0x02 #define W25X_ReadData 0x03 #define W25X_ChipErase 0xC7#define FLASH_ID 0XEF4015  //器件ID#define Dummy_Byte 0XFF#define WIP_Flag  0x01#define SPI_BUFSIZE 8 //SPI缓存的大小uint8_t   SPI_Tx_Buf[SPI_BUFSIZE];  //发送uint8_t   SPI_Rx_Buf[SPI_BUFSIZE];  //接收uint32_t ID = 0;volatile  uint8_t   SPIReadLength, SPIWriteLength;/** * @brief SPI user event handler. * @param event */void spi_event_handler(nrf_drv_spi_evt_t const * p_event,                       void *                    p_context){    spi_xfer_done = true;}/*向W25Q80中写入数据参数 reg 寄存器地址     data 要写入的数据*/void W25Q80_write_reg(int data){    spi_xfer_done = false;    SPIWriteLength = 1;    SPIReadLength = 0;    SPI_Tx_Buf[0] = data;      APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, SPI_Tx_Buf, SPIWriteLength, SPI_Rx_Buf, SPIReadLength));    while(spi_xfer_done == false);}/*从W25Q80中读取数据参数： reg 寄存器地址*/uint8_t W25Q80_read_reg(int reg){    spi_xfer_done = false;    SPI_Tx_Buf[0] = reg;    APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, SPI_Tx_Buf, 0, SPI_Rx_Buf,1));    while(spi_xfer_done == false);    return SPI_Rx_Buf[0];}/*读取W25Q80的器件ID*/uint32_t W25Q80_ReadID(void){    uint32_t temp = 0,temp0 = 0,temp1 = 0,temp2 = 0;    nrf_gpio_pin_clear(SPI_SS_PIN);  //片选有效    W25Q80_write_reg(W25X_JedecDeviceID);    temp0 = W25Q80_read_reg(0XFF);    temp1 = W25Q80_read_reg(0XFF);    temp2 = W25Q80_read_reg(0XFF);    nrf_gpio_pin_set(SPI_SS_PIN);  //片选无效    temp = (temp0 << 16)| (temp1 << 8) | temp2;    return temp;}/*写使能命令*/void W25Q80_WriteEnable(){    nrf_gpio_pin_clear(SPI_SS_PIN);  //片选有效    W25Q80_write_reg(W25X_WriteEnable);    nrf_gpio_pin_set(SPI_SS_PIN);  //片选有效}/*通过读状态寄存器等待FLASH芯片空闲*/void W25Q80_WaitForWriteEnd(){    unsigned char FLASH_Status = 0;    nrf_gpio_pin_clear(SPI_SS_PIN);  //片选有效    W25Q80_write_reg(W25X_ReadStatusReg); //发送读状态寄存器    do    {        FLASH_Status = W25Q80_read_reg(Dummy_Byte);    }    while((WIP_Flag & FLASH_Status) == 1);    nrf_gpio_pin_set(SPI_SS_PIN);  //片选无效    }/*擦除FLASH的扇区参数 SectorAddr 要擦除的扇区地址*/void W25Q80_FLASH_SectorErase(uint32_t SectorAddr){    W25Q80_WriteEnable();  //发送FLASH写使能命令    W25Q80_WaitForWriteEnd();  //等待写完成    nrf_gpio_pin_clear(SPI_SS_PIN);  //片选有效    W25Q80_write_reg(W25X_SectorErase);  //发送扇区擦除指令    W25Q80_write_reg((SectorAddr & 0XFF0000) >> 16); //发送扇区擦除地址的高位    W25Q80_write_reg((SectorAddr & 0XFF00) >> 8);    W25Q80_write_reg(SectorAddr & 0XFF);    nrf_gpio_pin_set(SPI_SS_PIN);  //片选无效    W25Q80_WaitForWriteEnd();  //等待擦除完成}/*FLASH页写入指令参数：备注：使用页写入指令最多可以一次向FLASH传输256个字节的数据*/void W25Q80_FLASH_PageWrite(unsigned char* pBuffer, uint32_t WriteAddr, uint16_t NumByteToWrite){    W25Q80_WriteEnable();  //发送FLASH写使能命令    nrf_gpio_pin_clear(SPI_SS_PIN);  //片选有效    W25Q80_write_reg(W25X_PageProgram);  //发送写指令    W25Q80_write_reg((WriteAddr & 0XFF0000) >> 16); //发送写地址的高位    W25Q80_write_reg((WriteAddr & 0XFF00) >> 8);    W25Q80_write_reg(WriteAddr & 0XFF);    if(NumByteToWrite > 256)    {        NRF_LOG_INFO("write too large!\r\n");        return ;    }    while(NumByteToWrite--)    {        W25Q80_write_reg(*pBuffer);        pBuffer++;    }    nrf_gpio_pin_set(SPI_SS_PIN);  //片选无效    W25Q80_WaitForWriteEnd();  //等待写完成}/*从FLASH中读取数据*/void W25Q80_Flash_BufferRead(uint8_t* pBuffer, uint32_t ReadAddr, uint16_t NumByteToRead){    nrf_gpio_pin_clear(SPI_SS_PIN);  //片选有效    W25Q80_write_reg(W25X_ReadData);  //发送写指令    W25Q80_write_reg((ReadAddr & 0XFF0000) >> 16); //发送写地址的高位    W25Q80_write_reg((ReadAddr & 0XFF00) >> 8);    W25Q80_write_reg(ReadAddr & 0XFF);    while(NumByteToRead--)    {        *pBuffer = W25Q80_read_reg(Dummy_Byte);        pBuffer++;    }    nrf_gpio_pin_set(SPI_SS_PIN);  //片选无效   }/*全片擦除*/void W25Q80_Chip_Erase(){    W25Q80_WriteEnable();  //发送FLASH写使能命令    nrf_gpio_pin_clear(SPI_SS_PIN);  //片选有效    W25Q80_write_reg(W25X_ChipErase);  //全片擦除    nrf_gpio_pin_set(SPI_SS_PIN);  //片选无效    W25Q80_WaitForWriteEnd();  //等待写完成}void W25Q80_init(){    //初始化SPI引脚    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;//    spi_config.ss_pin   = SPI_SS_PIN;  //把SS引脚禁用    spi_config.miso_pin = SPI_MISO_PIN;    spi_config.mosi_pin = SPI_MOSI_PIN;    spi_config.sck_pin  = SPI_SCK_PIN;    nrf_gpio_cfg_output(SPI_SS_PIN);    nrf_gpio_pin_clear(SPI_SS_PIN);  //片选有效    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));    nrf_delay_ms(500);    nrf_gpio_pin_set(15);    //读取寄存器的值，判断器件是否存在     ID=W25Q80_ReadID();    if(ID != FLASH_ID)    {        NRF_LOG_INFO("init w25q80 error\r\n");    }    else    {        NRF_LOG_INFO("init w25q80 ok!\r\n");        NRF_LOG_INFO("FLASH ID is %X",ID);    }}#define countof(a)      (sizeof(a) / sizeof(*(a)))#define  BufferSize (countof(Tx_Buffer)-1)int main(void){    unsigned char Tx_Buffer[] = "This is a demo about FLASH WRITE BY Manual";    unsigned char Rx_Buffer[250];    bsp_board_init(BSP_INIT_LEDS);  //初始化开发板上的指示灯    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));    NRF_LOG_DEFAULT_BACKENDS_INIT();    NRF_LOG_INFO("SPI example started.");    W25Q80_init();    W25Q80_Chip_Erase();  //全片擦除   //全片擦除所需的时间比较长    W25Q80_FLASH_PageWrite(Tx_Buffer,0x00000,BufferSize);    NRF_LOG_INFO("%s\r\n",Tx_Buffer);    W25Q80_Flash_BufferRead(Rx_Buffer,0x000000,BufferSize);    NRF_LOG_INFO("%s\r\n",Rx_Buffer);    while (1)    {        // Reset rx buffer and transfer done flag        spi_xfer_done = false;        NRF_LOG_FLUSH();        nrf_delay_ms(200);    }}
    

参考资料：

1 nRF52832数据手册

2 《低功耗蓝牙技术快速入门》

3 W25Q80数据手册

4 《零死角玩转STM32F103指南者》