NRF24L01使用的SPI协议通信，这里并没有用到s3c2440自带的SPI功能，而是直接用IO口模拟SPI。而根据Datasheet所示，NRF24L01的SPI接速率为0~8Mbps，因此需要在读写时序上加上适当的延时。
驱动程序：
/************************************************************/
//文件名：nrf24l01.c
//功能:linux下的nrf24l01驱动程序
//使用说明: (1)
// (2)
// (3)
// (4)
//作者:jammy-lee
//日期：2010-01-11
/************************************************************/
#include <linux/config.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/miscdevice.h>
#include <linux/devfs_fs_kernel.h>
#include <asm/uaccess.h>
#include <asm/hardware.h>
#include <asm/arch/regs-gpio.h>
typedef unsigned int uint16 ;
typedef unsigned char uint8 ;
/*
//和引脚相关的宏定义
#define CE S3C2410_GPF3
#define CE_OUTP S3C2410_GPF3_OUTP
#define SCK S3C2410_GPF4
#define SCK_OUTP S3C2410_GPF4_OUTP
#define MISO S3C2410_GPG3
#define MISO_INP S3C2410_GPG3_INP
#define IRQ S3C2410_GPG0
#define IRQ_OUTP S3C2410_GPG0_OUTP
#define MOSI S3C2410_GPG5
#define MOSI_OUTP S3C2410_GPG5_OUTP
#define CSN S3C2410_GPG6
#define CSN_OUTP S3C2410_GPG6_OUTP
*/
//和引脚相关的宏定义
#define CSN S3C2410_GPF3
#define CSN_OUTP S3C2410_GPF3_OUTP
#define MOSI S3C2410_GPF4
#define MOSI_OUTP S3C2410_GPF4_OUTP
#define IRQ S3C2410_GPG3
#define IRQ_INP S3C2410_GPG3_INP
#define MISO S3C2410_GPG0
#define MISO_INP S3C2410_GPG0_INP
#define SCK S3C2410_GPG5
#define SCK_OUTP S3C2410_GPG5_OUTP
#define CE S3C2410_GPG6
#define CE_OUTP S3C2410_GPG6_OUTP
#define DEVICE_NAME "NRF24L01" //设备名称，在可以 /proc/devices 查看
#define NRF24L01_MAJOR 241 //主设备号
#define TxBufSize 32
uint8 TxBuf[TxBufSize]={
0x01,0x02,0x03,0x4,0x05,0x06,0x07,0x08,
0x09,0x10,0x11,0x12,0x13,0x14,0x15,0x16,
0x17,0x18,0x19,0x20,0x21,0x22,0x23,0x24,
0x25,0x26,0x27,0x28,0x29,0x30,0x31,0x32,
};
//NRF24L01端口定义
#define CE_OUT s3c2410_gpio_cfgpin(CE, CE_OUTP) //数据线设置为输出
#define CE_UP s3c2410_gpio_pullup(CE, 1) //打开上拉电阻
#define CE_L s3c2410_gpio_setpin(CE, 0) //拉低数据线电平
#define CE_H s3c2410_gpio_setpin(CE, 1) //拉高数据线电平
#define SCK_OUT s3c2410_gpio_cfgpin(SCK, SCK_OUTP) //数据线设置为输出
#define SCK_UP s3c2410_gpio_pullup(SCK, 1) //打开上拉电阻
#define SCK_L s3c2410_gpio_setpin(SCK, 0) //拉低数据线电平
#define SCK_H s3c2410_gpio_setpin(SCK, 1) //拉高数据线电平
#define MISO_IN s3c2410_gpio_cfgpin(MISO, MISO_INP) //数据线设置为输出
#define MISO_UP s3c2410_gpio_pullup(MISO, 1) //打开上拉电阻
#define MISO_STU s3c2410_gpio_getpin(MISO) //数据状态
#define IRQ_IN s3c2410_gpio_cfgpin(IRQ, IRQ_INP) //数据线设置为输出
#define IRQ_UP s3c2410_gpio_pullup(IRQ, 1) //打开上拉电阻
#define IRQ_L s3c2410_gpio_setpin(IRQ, 0) //拉低数据线电平
#define IRQ_H s3c2410_gpio_setpin(IRQ, 1) //拉高数据线电平
#define MOSI_OUT s3c2410_gpio_cfgpin(MOSI, MOSI_OUTP) //数据线设置为输出
#define MOSI_UP s3c2410_gpio_pullup(MOSI, 1) //打开上拉电阻
#define MOSI_L s3c2410_gpio_setpin(MOSI, 0) //拉低数据线电平
#define MOSI_H s3c2410_gpio_setpin(MOSI, 1) //拉高数据线电平
#define CSN_OUT s3c2410_gpio_cfgpin(CSN, CSN_OUTP) //数据线设置为输出
#define CSN_UP s3c2410_gpio_pullup(CSN, 1) //打开上拉电阻
#define CSN_L s3c2410_gpio_setpin(CSN, 0) //拉低数据线电平
#define CSN_H s3c2410_gpio_setpin(CSN, 1) //拉高数据线电平
//NRF24L01
#define TX_ADR_WIDTH 5 // 5 uint8s TX address width
#define RX_ADR_WIDTH 5 // 5 uint8s RX address width
#define TX_PLOAD_WIDTH 32 // 20 uint8s TX payload
#define RX_PLOAD_WIDTH 32 // 20 uint8s TX payload
uint8 const TX_ADDRESS[TX_ADR_WIDTH]= {0x34,0x43,0x10,0x10,0x01}; //本地地址
uint8 const RX_ADDRESS[RX_ADR_WIDTH]= {0x34,0x43,0x10,0x10,0x01}; //接收地址
//NRF24L01寄存器指令
#define READ_REG 0x00 // 读寄存器指令
#define WRITE_REG 0x20 // 写寄存器指令
#define RD_RX_PLOAD 0x61 // 读取接收数据指令
#define WR_TX_PLOAD 0xA0 // 写待发数据指令
#define FLUSH_TX 0xE1 // 冲洗发送 FIFO指令
#define FLUSH_RX 0xE2 // 冲洗接收 FIFO指令
#define REUSE_TX_PL 0xE3 // 定义重复装载数据指令
#define NOP 0xFF // 保留
//SPI(nRF24L01)寄存器地址
#define CONFIG 0x00 // 配置收发状态，CRC校验模式以及收发状态响应方式
#define EN_AA 0x01 // 自动应答功能设置
#define EN_RXADDR 0x02 // 可用信道设置
#define SETUP_AW 0x03 // 收发地址宽度设置
#define SETUP_RETR 0x04 // 自动重发功能设置
#define RF_CH 0x05 // 工作频率设置
#define RF_SETUP 0x06 // 发射速率、功耗功能设置
#define STATUS 0x07 // 状态寄存器
#define OBSERVE_TX 0x08 // 发送监测功能
#define CD 0x09 // 地址检测
#define RX_ADDR_P0 0x0A // 频道0接收数据地址
#define RX_ADDR_P1 0x0B // 频道1接收数据地址
#define RX_ADDR_P2 0x0C // 频道2接收数据地址
#define RX_ADDR_P3 0x0D // 频道3接收数据地址
#define RX_ADDR_P4 0x0E // 频道4接收数据地址
#define RX_ADDR_P5 0x0F // 频道5接收数据地址
#define TX_ADDR 0x10 // 发送地址寄存器
#define RX_PW_P0 0x11 // 接收频道0接收数据长度
#define RX_PW_P1 0x12 // 接收频道0接收数据长度
#define RX_PW_P2 0x13 // 接收频道0接收数据长度
#define RX_PW_P3 0x14 // 接收频道0接收数据长度
#define RX_PW_P4 0x15 // 接收频道0接收数据长度
#define RX_PW_P5 0x16 // 接收频道0接收数据长度
#define FIFO_STATUS 0x17 // FIFO栈入栈出状态寄存器设置
uint8 init_NRF24L01(void);
uint8 SPI_RW(uint8 tmp);
uint8 SPI_Read(uint8 reg);
void SetRX_Mode(void);
uint8 SPI_RW_Reg(uint8 reg, uint8 value);
uint8 SPI_Read_Buf(uint8 reg, uint8 *pBuf, uint8 uchars);
uint8 SPI_Write_Buf(uint8 reg, uint8 *pBuf, uint8 uchars);
unsigned char nRF24L01_RxPacket(unsigned char* rx_buf);
void nRF24L01_TxPacket(unsigned char * tx_buf);
//全局变量
uint8 opencount = 0;
//
uint8 sta; //状态标志
#define RX_DR 6
#define TX_DS 5
#define MAX_RT 4
//NRF24L01初始化
uint8 init_NRF24L01(void)
{
/*
CE_UP;
SCK_UP;
MISO_UP;
IRQ_UP;
MOSI_UP;
CSN_UP;
*/
MISO_UP;
CE_OUT;
CSN_OUT;
SCK_OUT;
MOSI_OUT;
MISO_IN;
IRQ_IN;
udelay(500);
CE_L; // chip enable
ndelay(60);
CSN_H; // Spi disable
ndelay(60);
SCK_L; // Spi clock line init high
ndelay(60);
SPI_Write_Buf(WRITE_REG + TX_ADDR, TX_ADDRESS, TX_ADR_WIDTH); // 写本地地址
SPI_Write_Buf(WRITE_REG + RX_ADDR_P0, RX_ADDRESS, RX_ADR_WIDTH); // 写接收端地址
SPI_RW_Reg(WRITE_REG + EN_AA, 0x01); // 频道0自动 ACK应答允许
SPI_RW_Reg(WRITE_REG + EN_RXADDR, 0x01); // 允许接收地址只有频道0，如果需要多频道可以参考Page21
SPI_RW_Reg(WRITE_REG + RF_CH, 0); // 设置信道工作为2.4GHZ，收发必须一致
SPI_RW_Reg(WRITE_REG + RX_PW_P0, RX_PLOAD_WIDTH); //设置接收数据长度，本次设置为32字节
SPI_RW_Reg(WRITE_REG + RF_SETUP, 0x07); //设置发射速率为1MHZ，发射功率为最大值0dB
SPI_RW_Reg(WRITE_REG + CONFIG, 0x0f); // IRQ收发完成中断响应，16位CRC ，主接收
mdelay(1000);
nRF24L01_TxPacket(TxBuf);
SPI_RW_Reg(WRITE_REG+STATUS,0XFF);
printk("test 1 \n");
mdelay(1000);
/*
nRF24L01_TxPacket(TxBuf);
SPI_RW_Reg(WRITE_REG+STATUS,0XFF);
printk("test 2 \n");
mdelay(1000);
nRF24L01_TxPacket(TxBuf);
SPI_RW_Reg(WRITE_REG+STATUS,0XFF);
printk("test 3 \n");
mdelay(1000);
nRF24L01_TxPacket(TxBuf);
SPI_RW_Reg(WRITE_REG+STATUS,0XFF);
printk("test 4 \n");
mdelay(1000);
*/
return (1);
}
//函数：uint8 SPI_RW(uint8 tmp)
//功能：NRF24L01的SPI写时序tmp
uint8 SPI_RW(uint8 tmp)
{
uint8 bit_ctr;
for(bit_ctr=0 ;bit_ctr<8 ;bit_ctr++) // output 8-bit
{
if(tmp & 0x80) // output 'tmp', MSB to MOSI
MOSI_H;
else
MOSI_L;
tmp <<= 1; // shift next bit into MSB..
SCK_H; // Set SCK high..
ndelay(60);
tmp |= MISO_STU; // capture current MISO bit
SCK_L; // ..then set SCK low again
ndelay(60);
}
return(tmp); // return read tmp
}
//函数：uint8 SPI_Read(uint8 reg)
//功能：NRF24L01的SPI时序
uint8 SPI_Read(uint8 reg)
{
uint8 reg_val;
CSN_L; // CSN low, initialize SPI communication...
ndelay(60);
SPI_RW(reg); // Select register to read from..
reg_val = SPI_RW(0); // ..then read registervalue
CSN_H; // CSN high, terminate SPI communication
ndelay(60);
return(reg_val); // return register value
}
//功能：NRF24L01读写寄存器函数
uint8 SPI_RW_Reg(uint8 reg, uint8 value)
{
uint8 status;
CSN_L; // CSN low, init SPI transaction
ndelay(60);
status = SPI_RW(reg); // select register
SPI_RW(value); // ..and write value to it..
CSN_H; // CSN high again
ndelay(60);
return(status); // return nRF24L01 status uint8
}
//函数：uint8 SPI_Read_Buf(uint8 reg, uint8 *pBuf, uint8 uchars)
//功能: 用于读数据，reg：为寄存器地址，pBuf：为待读出数据地址，uchars：读出数据的个数
uint8 SPI_Read_Buf(uint8 reg, uint8 *pBuf, uint8 uchars)
{
uint8 status,uint8_ctr;
CSN_L; // Set CSN low, init SPI tranaction
ndelay(60);
status = SPI_RW(reg); // Select register to write to and read status uint8
for(uint8_ctr=0;uint8_ctr<uchars;uint8_ctr++)
{
pBuf[uint8_ctr] = SPI_RW(0); //
ndelay(20);
}
CSN_H;
ndelay(60);
return(status); // return nRF24L01 status uint8
}
//函数：uint8 SPI_Write_Buf(uint8 reg, uint8 *pBuf, uint8 uchars)
//功能: 用于写数据：为寄存器地址，pBuf：为待写入数据地址，uchars：写入数据的个数
uint8 SPI_Write_Buf(uint8 reg, uint8 *pBuf, uint8 uchars)
{
uint8 status,uint8_ctr;
CSN_L; //SPI使能
ndelay(60);
status = SPI_RW(reg);
for(uint8_ctr=0; uint8_ctr<uchars; uint8_ctr++) //
{
SPI_RW(*pBuf++);
ndelay(20);
}
CSN_H; //关闭SPI
ndelay(60);
return(status); //
}
//函数：void SetRX_Mode(void)
//功能：数据接收配置
void SetRX_Mode(void)
{
CE_L;
ndelay(60);
// SPI_RW_Reg(WRITE_REG + CONFIG, 0x0f); // IRQ收发完成中断响应，16位CRC ，主接收
//udelay(1);
CE_H;
udelay(130);
}
//函数：unsigned char nRF24L01_RxPacket(unsigned char* rx_buf)
//功能：数据读取后放如rx_buf接收缓冲区中
unsigned char nRF24L01_RxPacket(unsigned char* rx_buf)
{
unsigned char revale=0;
sta=SPI_Read(STATUS); // 读取状态寄存其来判断数据接收状况
if(sta & (1<<RX_DR)) // 判断是否接收到数据
{
CE_L; //SPI使能
udelay(50);
SPI_Read_Buf(RD_RX_PLOAD,rx_buf,TX_PLOAD_WIDTH);// read receive payload from RX_FIFO buffer
revale =1; //读取数据完成标志
}
SPI_RW_Reg(WRITE_REG+STATUS,sta); //接收到数据后RX_DR,TX_DS,MAX_PT都置高为1，通过写1来清楚中断标志
return revale;
}
//函数：void nRF24L01_TxPacket(unsigned char * tx_buf)
//功能：发送 tx_buf中数据
void nRF24L01_TxPacket(unsigned char * tx_buf)
{
CE_L; //StandBy I模式
ndelay(60);
SPI_Write_Buf(WRITE_REG + RX_ADDR_P0, TX_ADDRESS, TX_ADR_WIDTH); // 装载接收端地址
SPI_Write_Buf(WR_TX_PLOAD, tx_buf, TX_PLOAD_WIDTH); // 装载数据
SPI_RW_Reg(WRITE_REG + CONFIG, 0x0e); // IRQ收发完成中断响应，16位CRC，主发送
CE_H; //置高CE，激发数据发送
udelay(10);
}
//文件的写函数
static ssize_t nrf24l01_write(struct file *filp, const char *buffer,
size_t count, loff_t *ppos)
{
if( copy_from_user( &TxBuf, buffer, count ) ); //从内核空间复制到用户空间
{
printk("Can't Send Data !");
return -EFAULT;
}
nRF24L01_TxPacket(TxBuf);
SPI_RW_Reg(WRITE_REG+STATUS,0XFF);
printk("OK! \n");
return(10);
}
//的读函数
static ssize_t nrf24l01_read(struct file *filp, char *buffer,
size_t count, loff_t *ppos)
{
nRF24L01_TxPacket(TxBuf);
SPI_RW_Reg(WRITE_REG+STATUS,0XFF);
printk("read \n");
return (10);
}
static int nrf24l01_open(struct inode *node, struct file *file)
{
uint8 flag = 0;
if(opencount == 1)
return -EBUSY;
flag = init_NRF24L01();
mdelay(100);
if(flag == 0)
{
printk("uable to open device!\n");
return -1;
}
else
{
opencount++;
printk("device opened !\n");
return 0;
}
}
static int nrf24l01_release(struct inode *node, struct file *file)
{
opencount--;
printk(DEVICE_NAME " released !\n");
return 0;
}
static struct file_operations nrf24l01_fops = {
.owner = THIS_MODULE,
.open = nrf24l01_open,
.write = nrf24l01_write,
.read = nrf24l01_read,
.release = nrf24l01_release,
};
static int __init nrf24l01_init(void)
{
int ret;
printk("Initial driver for NRF24L01......................\n");
ret = register_chrdev(NRF24L01_MAJOR, DEVICE_NAME, &nrf24l01_fops);
mdelay(10);
if (ret < 0)
{
printk(DEVICE_NAME " can't register major number\n");
return ret;
}
else
{
printk(DEVICE_NAME " register success\n");
return 0;
}
}
static void __exit nrf24l01_exit(void)
{
unregister_chrdev(NRF24L01_MAJOR, DEVICE_NAME);
printk("NRF24L01 unregister success \n");
}
module_init(nrf24l01_init);
module_exit(nrf24l01_exit);
MODULE_AUTHOR("jammy_lee@163.com");
MODULE_DESCRIPTION("nrf24l01 driver for TQ2440");
MODULE_LICENSE("GPL");
测试程序：
/************************************************************/
//文件名：test_ds18b20.c
//功能:测试linux下的ds18b20程序
//使用说明: (1)
// (2)
// (3)
// (4)
//作者:jammy-lee
//日期:2010-01-18
/************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/select.h>
#include <sys/time.h>
#include <errno.h>
unsigned char TxBuf[32] = {0x00};
int main(void)
{
int fd = -1;
int count = 1;
//fd = open("/dev/nrf24l01", 0);
fd = open("/dev/nrf24l01", O_RDWR); //打开nrf24l01为可读写文件
if(fd < 0)
{
perror("Can't open /dev/nrf24l01 \n");
exit(1);
}
printf("open /dev/nrf24l01 success \n");
while(count <= 5)
{
write(fd, &TxBuf , sizeof(TxBuf));
printf("Sending %d time \n", count);
usleep(100*1000);
count++;
}
close(fd);
}
来源：http://blog.163.com/prevBlogPerma.do?host=jammy_lee&srl=101195478201016112945395&mode=prev
作者：jackxiang@向东博客 专注WEB应用 构架之美 --- 构架之美，在于尽态极妍 | 应用之美，在于药到病除
地址：https://jackxiang.com/post/3132/
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