NRF24L01使用SPI總線與主機通信，沒有SPI端口的設備可以使用IO口進行模擬。

關于SPI：
SPI是一種四線串行總線，
SCLK： 串行時鐘線
MOSI： 總線主機輸出/ 從機輸入
MISO： 總線主機輸入/ 從機輸出;
SS： 從機使能數(shù)據(jù)傳輸方式
通訊是通過數(shù)據(jù)交換完成的，這里先要知道SPI是串行通訊協(xié)議，也就是說數(shù)據(jù)是一位一位的傳輸?shù)?。這就是SCLK時鐘線存在的原因，由SCK提供時鐘脈沖，SDI，SDO則基于此脈沖完成數(shù)據(jù)傳輸。數(shù)據(jù)輸出通過 SDO線，數(shù)據(jù)在時鐘上升沿或下降沿時改變，在緊接著的下降沿或上升沿被讀取。完成一位數(shù)據(jù)傳輸，輸入也使用同樣原理。這樣，在至少8次時鐘信號的改變（上沿和下沿為一次），就可以完成8位數(shù)據(jù)的傳輸。

NRF24L01寄存器說明：
還是看說明書吧，dbank驅動源碼在下一頁。驅動源碼：

#include #include #include #include #include #include 

#include#include#include#include#include#include#include#include#include#include

typedef unsigned int uint16;
typedef unsigned char uint8;

/* 引腳相關定義 */
#define CSN S3C2410_GPF(4)
#define CSN_OUTP S3C2410_GPIO_OUTPUT
#define MOSI S3C2410_GPG(0)
#define MOSI_OUTP S3C2410_GPIO_OUTPUT
#define IRQ S3C2410_GPG(1)
#define IRQ_INP S3C2410_GPIO_INPUT
#define MISO S3C2410_GPG(6)
#define MISO_INP S3C2410_GPIO_INPUT
#define SCK S3C2410_GPG(7)
#define SCK_OUTP S3C2410_GPIO_OUTPUT
#define CE S3C2410_GPG(11)
#define CE_OUTP S3C2410_GPIO_OUTPUT

#define DEVICE_NAME “NRF24L01”

#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端口定義

#define CE_OUT s3c2410_gpio_cfgpin(CE, CE_OUTP) //數(shù)據(jù)線設置為輸出

#define CE_UP s3c2410_gpio_pullup(CE, 1) //打開上拉電阻

#define CE_L s3c2410_gpio_setpin(CE, 0) //拉低數(shù)據(jù)線電平

#define CE_H s3c2410_gpio_setpin(CE, 1) //拉高數(shù)據(jù)線電平

#define SCK_OUT s3c2410_gpio_cfgpin(SCK, SCK_OUTP) //數(shù)據(jù)線設置為輸出

#define SCK_H s3c2410_gpio_setpin(SCK, 1) //拉高數(shù)據(jù)線電平

#define SCK_L s3c2410_gpio_setpin(SCK, 0) //拉高數(shù)據(jù)線電平

#define MISO_IN s3c2410_gpio_cfgpin(MISO, MISO_INP) //數(shù)據(jù)線設置為輸出

#define MISO_UP s3c2410_gpio_pullup(MISO, 1) //打開上拉電阻

#define MISO_STU s3c2410_gpio_getpin(MISO) //數(shù)據(jù)狀態(tài)

#define IRQ_IN s3c2410_gpio_cfgpin(IRQ, IRQ_INP) //數(shù)據(jù)線設置為輸出

#define IRQ_UP s3c2410_gpio_pullup(IRQ, 1) //打開上拉電阻

#define IRQ_L s3c2410_gpio_setpin(IRQ, 0) //拉低數(shù)據(jù)線電平

#define IRQ_H s3c2410_gpio_setpin(IRQ, 1) //拉高數(shù)據(jù)線電平

#define MOSI_OUT s3c2410_gpio_cfgpin(MOSI, MOSI_OUTP) //數(shù)據(jù)線設置為輸出

#define MOSI_UP s3c2410_gpio_pullup(MOSI, 1) //打開上拉電阻

#define MOSI_L s3c2410_gpio_setpin(MOSI, 0) //拉低數(shù)據(jù)線電平

#define MOSI_H s3c2410_gpio_setpin(MOSI, 1) //拉高數(shù)據(jù)線電平

#define CSN_OUT s3c2410_gpio_cfgpin(CSN, CSN_OUTP) //數(shù)據(jù)線設置為輸出

#define CSN_UP s3c2410_gpio_pullup(CSN, 1) //打開上拉電阻

#define CSN_L s3c2410_gpio_setpin(CSN, 0) //拉低數(shù)據(jù)線電平

#define CSN_H s3c2410_gpio_setpin(CSN, 1) //拉高數(shù)據(jù)線電平

//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 TX_ADDRESS[TX_ADR_WIDTH] = { 0x34, 0x43, 0x10, 0x10, 0x01 }; //本地地址

uint8 RX_ADDRESS[RX_ADR_WIDTH] = { 0x34, 0x43, 0x10, 0x10, 0x01 }; //接收地址

//NRF24L01寄存器指令

#define READ_REG 0x00 // 讀寄存器指令

#define WRITE_REG 0x20 // 寫寄存器指令

#define RD_RX_PLOAD 0x61 // 讀取接收數(shù)據(jù)指令

#define WR_TX_PLOAD 0xA0 // 寫待發(fā)數(shù)據(jù)指令

#define FLUSH_TX 0xE1 // 沖洗發(fā)送 FIFO指令

#define FLUSH_RX 0xE2 // 沖洗接收 FIFO指令

#define REUSE_TX_PL 0xE3 // 定義重復裝載數(shù)據(jù)指令

#define NOP 0xFF // 保留

//SPI(nRF24L01)寄存器地址

#define CONFIG 0x00 // 配置收發(fā)狀態(tài)，CRC校驗模式以及收發(fā)狀態(tài)響應方式

#define EN_AA 0x01 // 自動應答功能設置

#define EN_RXADDR 0x02 // 可用信道設置

#define SETUP_AW 0x03 // 收發(fā)地址寬度設置

#define SETUP_RETR 0x04 // 自動重發(fā)功能設置

#define RF_CH 0x05 // 工作頻率設置

#define RF_SETUP 0x06 // 發(fā)射速率、功耗功能設置

#define STATUS 0x07 // 狀態(tài)寄存器

#define OBSERVE_TX 0x08 // 發(fā)送監(jiān)測功能

#define CD 0x09 // 地址檢測

#define RX_ADDR_P0 0x0A // 頻道0接收數(shù)據(jù)地址

#define RX_ADDR_P1 0x0B // 頻道1接收數(shù)據(jù)地址

#define RX_ADDR_P2 0x0C // 頻道2接收數(shù)據(jù)地址

#define RX_ADDR_P3 0x0D // 頻道3接收數(shù)據(jù)地址

#define RX_ADDR_P4 0x0E // 頻道4接收數(shù)據(jù)地址

#define RX_ADDR_P5 0x0F // 頻道5接收數(shù)據(jù)地址

#define TX_ADDR 0x10 // 發(fā)送地址寄存器

#define RX_PW_P0 0x11 // 接收頻道0接收數(shù)據(jù)長度

#define RX_PW_P1 0x12 // 接收頻道0接收數(shù)據(jù)長度

#define RX_PW_P2 0x13 // 接收頻道0接收數(shù)據(jù)長度

#define RX_PW_P3 0x14 // 接收頻道0接收數(shù)據(jù)長度

#define RX_PW_P4 0x15 // 接收頻道0接收數(shù)據(jù)長度

#define RX_PW_P5 0x16 // 接收頻道0接收數(shù)據(jù)長度

#define FIFO_STATUS 0x17 // FIFO棧入棧出狀態(tài)寄存器設置

/* 打開計數(shù) */
uint open_count = 0;

/* 狀態(tài)標識 */
uint8 receive_state;

int get_data=0;

wait_queue_head_t read_queue; //讀取等待隊列

#define RX_DR 6
#define TX_DS 5
#define MAX_RT 4

/* unit8 SPI_RW(uint8 tmp)
* SPI寫時序,寫一個字節(jié)到MOSI同時從MISO中讀取一個字節(jié) */
uint8 SPI_RW(uint8 tmp)
{ uint8 bit_ctl;

for (bit_ctl = 0; bit_ctl < 8;bit_ctl++){
if(tmp & 0x80)
MOSI_H;
else
MOSI_L;

tmp = tmp << 1; //Shift next bit into MSB

SCK_H; //Set SCK high

ndelay(60);

tmp |= MISO_STU; //Capture current MISO bit

SCK_L;

ndelay(60);
}
return tmp;
}

/*
* 函數(shù)：uint8 SPI_Read(uint8 reg)
* 功能：NRF24L01的SPI時序
*/
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讀寫寄存器函數(shù)

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

}

//函數(shù)：uint8 SPI_Read_Buf(uint8 reg, uint8 *pBuf, uint8 uchars)

//功能: 用于讀數(shù)據(jù)，reg：為寄存器地址，pBuf：為待讀出數(shù)據(jù)地址，uchars：讀出數(shù)據(jù)的個數(shù)

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

}

//函數(shù)：uint8 SPI_Write_Buf(uint8 reg, uint8 *pBuf, uint8 uchars)

//功能: 用于寫數(shù)據(jù)：為寄存器地址，pBuf：為待寫入數(shù)據(jù)地址，uchars：寫入數(shù)據(jù)的個數(shù)

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; //關閉SPI

ndelay(60);
return (status); //
}

//函數(shù)：void SetRX_Mode(void)

//功能：數(shù)據(jù)接收配置

void SetRX_Mode(void)
{

CE_L;
ndelay(60);
// SPI_RW_Reg(WRITE_REG + CONFIG, 0x0f); // IRQ收發(fā)完成中斷響應，16位CRC ，主接收

//udelay(1);

CE_H;
udelay(130);
}

//函數(shù)：unsigned char nRF24L01_RxPacket(unsigned char* rx_buf)

//功能：數(shù)據(jù)讀取后放如rx_buf接收緩沖區(qū)中

unsigned char nRF24L01_RxPacket(unsigned char *rx_buf)
{ unsigned char revale = 0;

receive_state = SPI_Read(STATUS); // 讀取狀態(tài)寄存其來判斷數(shù)據(jù)接收狀況

if (receive_state & (1 << RX_DR)) // 判斷是否接收到數(shù)據(jù)

{
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; //讀取數(shù)據(jù)完成標志

}
SPI_RW_Reg(WRITE_REG + STATUS, receive_state); //接收到數(shù)據(jù)后RX_DR,TX_DS,MAX_PT都置高為1，通過寫1來清楚中斷標志

return revale;
}

//函數(shù)：void nRF24L01_TxPacket(unsigned char * tx_buf)

//功能：發(fā)送 tx_buf中數(shù)據(jù)

void nRF24L01_TxPacket(unsigned char *tx_buf)
{ uint8 ret;
CE_L; //StandBy I模式

ndelay(60);
ret=SPI_Write_Buf(WRITE_REG + RX_ADDR_P0, TX_ADDRESS, TX_ADR_WIDTH); // 裝載接收端地址
printk(“ret=%cn”,ret);
ret=SPI_Write_Buf(WR_TX_PLOAD, tx_buf, TX_PLOAD_WIDTH); // 裝載數(shù)據(jù)
printk(“ret=%cn”,ret);

SPI_RW_Reg(WRITE_REG + CONFIG, 0x0e); // IRQ收發(fā)完成中斷響應，16位CRC，主發(fā)送

CE_H; //置高CE，激發(fā)數(shù)據(jù)發(fā)送

udelay(10);
}

static irqreturn_t nrf24l01_interrupt(int irq,void *dev_id)
{ uint8 state ;
state = SPI_Read(STATUS);
if(state & 0x10){
SPI_RW_Reg(WRITE_REG + STATUS , state); //如果是重發(fā)中斷則寫回清除中斷
}else if(state & 0x20){
SPI_RW_Reg(WRITE_REG + STATUS , state); //清除發(fā)送中斷
}else if ( state & 0x40){
get_data = 1;
nRF24L01_RxPacket(TxBuf);
wake_up_interruptible(&read_queue);
}
return IRQ_RETVAL(IRQ_HANDLED);
}

uint8 init_NRF24L01(void)
{ 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); // 寫本地地址

SPI_Write_Buf(WRITE_REG + RX_ADDR_P0, RX_ADDRESS, RX_ADR_WIDTH); // 寫接收端地址

SPI_RW_Reg(WRITE_REG + EN_AA, 0x01); // 頻道0自動 ACK應答允許

SPI_RW_Reg(WRITE_REG + EN_RXADDR, 0x01); // 允許接收地址只有頻道0，如果需要多頻道可以參考Page21

SPI_RW_Reg(WRITE_REG + RF_CH, 0); // 設置信道工作為2.4GHZ，收發(fā)必須一致

SPI_RW_Reg(WRITE_REG + RX_PW_P0, RX_PLOAD_WIDTH); //設置接收數(shù)據(jù)長度，本次設置為32字節(jié)

SPI_RW_Reg(WRITE_REG + RF_SETUP, 0x07); //設置發(fā)射速率為1MHZ，發(fā)射功率為最大值0dB

SPI_RW_Reg(WRITE_REG + CONFIG, 0x0f); // IRQ收發(fā)完成中斷響應，16位CRC ，主接收
mdelay(1000);
nRF24L01_TxPacket(TxBuf);
SPI_RW_Reg(WRITE_REG + STATUS, 0XFF);
printk(“test 1 n”);
mdelay(1000);
return 1;
}

static uint16 nrf24l01_poll(struct file *filp,struct poll_table_struct *wait)
{ uint16 mask = 0;
poll_wait(filp,&read_queue,wait);
if(get_data){
mask |= POLLIN|POLLRDNORM;
}

return mask;
} static ssize_t nrf24l01_write(struct file *filp,const char *buffer, size_t count,loff_t *ppos)
{ if(copy_from_user(TxBuf,buffer,count))
{
printk(“Can’t Send Data !”);
return -EFAULT;
}

nRF24L01_TxPacket(TxBuf);
SPI_RW_Reg(WRITE_REG + STATUS,0XFF);
printk(“Send OK n”);
return 10;
}

static ssize_t nrf24l01_read(struct file * filp,char *buffer,size_t count,loff_t *ppos)
{ unsigned long err;
if(!get_data){
if(filp->f_flags & O_NONBLOCK)
return -EAGAIN;
else
wait_event_interruptible(read_queue,get_data);
}
get_data = 0;
err = copy_to_user(buffer,TxBuf,min(TxBufSize,count));

printk(“read okn”);
return err ? -EFAULT : min(TxBufSize,count);
}

static int nrf24l01_open(struct inode *node, struct file *file)
{ uint8 flag = 0;
unsigned long err;
if (open_count == 1)
return -EBUSY;

flag = init_NRF24L01();

mdelay(100);
init_waitqueue_head(&read_queue);

err = request_irq(IRQ_EINT9,nrf24l01_interrupt,IRQ_TYPE_EDGE_FALLING,DEVICE_NAME,NULL);
if(err){
disable_irq(IRQ_EINT9);
free_irq(IRQ_EINT9,NULL);
}
if (flag == 0) {
printk(“uable to open device!n”);
return -1;
} else {
open_count++;
printk(“device opened !n”);
return 0;
}
}

static int nrf24l01_release(struct inode *node, struct file *file)
{ free_irq(IRQ_EINT9,NULL);
open_count–;
printk(DEVICE_NAME ” released !n”);
return 0;
}

static struct file_operations nrf24l01_fops = {
.owner = THIS_MODULE,
.open = nrf24l01_open,
.write = nrf24l01_write,
.poll = nrf24l01_poll,
.read = nrf24l01_read,
.release = nrf24l01_release,
};

static struct miscdevice nrf24l01_dev = {
.minor = MISC_DYNAMIC_MINOR,
.name = DEVICE_NAME,
.fops = &nrf24l01_fops,
};

static int __init nrf24l01_init(void)
{ int ret;

printk(“Initial driver for NRF24L01.n”);
ret = misc_register(&nrf24l01_dev);
mdelay(10);
if (ret < 0) {
printk(DEVICE_NAME ” can’t register major numbern”);
return ret;

} else {
printk(DEVICE_NAME ” register successn”);
return 0;
}
}

static void __exit nrf24l01_exit(void)
{ misc_deregister(&nrf24l01_dev);
printk(“NRF24L01 unregister success n”);
}

module_init(nrf24l01_init);
module_exit(nrf24l01_exit);
MODULE_AUTHOR(“Issac”);
MODULE_DESCRIPTION(“NRF24L01 Driver”);
MODULE_LICENSE(“GPL”);備注：不同管腳的定義可以自行修改。
我添加了poll方法 和接收中斷的處理
由于MSP的程序沒有調好，這個驅動還沒有進行測試。在內核中部署驅動：
將nrf24l01.c文件到源碼下driver/misc/ 目錄下
修改該目錄下的Kconfig文件
在合適位置添加

config NRF24L01tristate "NRF24L01 Single Chip 2.4 GHz Radio Transceiver"helpDriver for NRF24L01

修改Makefile添加

obj-$(CONFIG_NRF24L01)		+= nrf24l01.o

測試程序：僅測試了發(fā)送

#include 

#include

#include

#include

#include

#include

#include

#include

#include

#include

unsigned char TxBuf[32] = {
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,
};
int main(void)

{

int fd = -1;
int ret;
int count = 1;

fd = open(“/dev/NRF24L01”, O_RDWR);

if(fd < 0)

{

perror(“Can’t open /dev/nrf24l01 n”);

exit(1);

}

printf(“open /dev/nrf24l01 success n”);

while(count <= 5)
{

ret = write(fd, TxBuf , sizeof(TxBuf));

char *mesg = strerror(errno);

printf(“Sending %d time %d n”, count,ret);
printf(“Errno:%dn,Mesg:%sn”,errno,mesg);
usleep(100*1000);

count++;
}

close(fd);
}