写一个w25q256的spi驱动程序

以下是一个简单的W25Q256的SPI驱动程序的示例，仅供参考：

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "spi.h"

//W25Q256指令定义
#define W25Q256_CMD_WRITE_ENABLE         0x06
#define W25Q256_CMD_WRITE_DISABLE        0x04
#define W25Q256_CMD_READ_STATUS_REG1     0x05
#define W25Q256_CMD_READ_DATA            0x03
#define W25Q256_CMD_WRITE_DATA           0x02
#define W25Q256_CMD_ERASE_SECTOR         0x20
#define W25Q256_CMD_ERASE_BLOCK          0xD8
#define W25Q256_CMD_ERASE_CHIP           0xC7
#define W25Q256_CMD_POWER_DOWN           0xB9
#define W25Q256_CMD_POWER_UP             0xAB

//W25Q256状态寄存器定义
#define W25Q256_STATUS_BUSY              0x01
#define W25Q256_STATUS_WEL               0x02

/**
 * @brief 初始化 SPI 接口
 */
void w25q256_spi_init(void)
{
    //初始化 SPI 总线
    spi_init();
}

/**
 * @brief 写使能
 */
static void w25q256_write_enable(void)
{
    uint8_t cmd = W25Q256_CMD_WRITE_ENABLE;
    spi_cs_low(); //使能片选
    spi_write(&cmd, sizeof(cmd)); //发送指令
    spi_cs_high(); //禁用片选
}

/**
 * @brief 写禁止
 */
static void w25q256_write_disable(void)
{
    uint8_t cmd = W25Q256_CMD_WRITE_DISABLE;
    spi_cs_low(); //使能片选
    spi_write(&cmd, sizeof(cmd)); //发送指令
    spi_cs_high(); //禁用片选
}

/**
 * @brief 读取状态寄存器1
 * @return 状态寄存器1的值
 */
static uint8_t w25q256_read_status_reg1(void)
{
    uint8_t cmd = W25Q256_CMD_READ_STATUS_REG1;
    uint8_t status = 0;

    spi_cs_low(); //使能片选
    spi_write(&cmd, sizeof(cmd)); //发送指令
    spi_read(&status, sizeof(status)); //读取寄存器值
    spi_cs_high(); //禁用片选

    return status;
}

/**
 * @brief 等待W25Q256空闲
 */
static void w25q256_wait_busy(void)
{
    while (w25q256_read_status_reg1() & W25Q256_STATUS_BUSY); //等待忙标志位清零
}

/**
 * @brief 读取数据
 * @param addr 读取数据的起始地址
 * @param data 存放读取的数据缓冲区
 * @param len 读取数据的长度
 */
void w25q256_read_data(uint32_t addr, uint8_t *data, uint32_t len)
{
    uint8_t cmd[4];
    cmd[0] = W25Q256_CMD_READ_DATA;
    cmd[1] = (addr >> 16) & 0xFF;
    cmd[2] = (addr >> 8) & 0xFF;
    cmd[3] = addr & 0xFF;

    spi_cs_low(); //使能片选
    spi_write(cmd, sizeof(cmd)); //发送指令
    spi_read(data, len); //读取数据
    spi_cs_high(); //禁用片选
}

/**
 * @brief 写入数据
 * @param addr 写入数据的起始地址
 * @param data 存放写入的数据缓冲区
 * @param len 写入数据的长度
 */
void w25q256_write_data(uint32_t addr, const uint8_t *data, uint32_t len)
{
    uint32_t i = 0;
    uint8_t cmd[4];

    w25q256_write_enable(); //写使能

    cmd[0] = W25Q256_CMD_WRITE_DATA;
    cmd[1] = (addr >> 16) & 0xFF;
    cmd[2] = (addr >> 8) & 0xFF;
    cmd[3] = addr & 0xFF;

    spi_cs_low(); //使能片选
    spi_write(cmd, sizeof(cmd)); //发送指令
    spi_write(data, len); //写入数据
    spi_cs_high(); //禁用片选

    w25q256_wait_busy(); //等待操作完成

    w25q256_write_disable(); //写禁止
}

/**
 * @brief 擦除扇区
 * @param addr 擦除扇区的起始地址
 */
void w25q256_erase_sector(uint32_t addr)
{
    uint8_t cmd[4];

    w25q256_write_enable(); //写使能

    cmd[0] = W25Q256_CMD_ERASE_SECTOR;
    cmd[1] = (addr >> 16) & 0xFF;
    cmd[2] = (addr >> 8) & 0xFF;
    cmd[3] = addr & 0xFF;

    spi_cs_low(); //使能片选
    spi_write(cmd, sizeof(cmd)); //发送指令
    spi_cs_high(); //禁用片选

    w25q256_wait_busy(); //等待操作完成

    w25q256_write_disable(); //写禁止
}

/**
 * @brief 擦除块
 * @param addr 擦除块的起始地址
 */
void w25q256_erase_block(uint32_t addr)
{
    uint8_t cmd[4];

    w25q256_write_enable(); //写使能

    cmd[0] = W25Q256_CMD_ERASE_BLOCK;
    cmd[1] = (addr >> 16) & 0xFF;
    cmd[2] = (addr >> 8) & 0xFF;
    cmd[3] = addr & 0xFF;

    spi_cs_low(); //使能片选
    spi_write(cmd, sizeof(cmd)); //发送指令
    spi_cs_high(); //禁用片选

    w25q256_wait_busy(); //等待操作完成

    w25q256_write_disable(); //写禁止
}

/**
 * @brief 擦除整个芯片
 */
void w25q256_erase_chip(void)
{
    uint8_t cmd = W25Q256_CMD_ERASE_CHIP;

    w25q256_write_enable(); //写使能

    spi_cs_low(); //使能片选
    spi_write(&cmd, sizeof(cmd)); //发送指令
    spi_cs_high(); //禁用片选

    w25q256_wait_busy(); //等待操作完成

    w25q256_write_disable(); //写禁止
}

/**
 * @brief 控制W25Q256进入掉电模式
 */
void w25q256_power_down(void)
{
    uint8_t cmd = W25Q256_CMD_POWER_DOWN;

    spi_cs_low(); //使能片选
    spi_write(&cmd, sizeof(cmd)); //发送指令
    spi_cs_high(); //禁用片选
}

/**
 * @brief 控制W25Q256退出掉电模式
 */
void w25q256_power_up(void)
{
    uint8_t cmd = W25Q256_CMD_POWER_UP;

    spi_cs_low(); //使能片选
    spi_write(&cmd, sizeof(cmd)); //发送指令
    spi_cs_high(); //禁用片选

    //W25Q256需要一定时间从掉电模式恢复，需要等待
    delay_ms(10);
}

由于不同的硬件平台和SPI接口实现有所不同，上述代码仅供参考。在使用时，请根据实际情况进行相应的修改。