糊涂塔克学习笔记01 Arduino+nRF24L01
各位大大好，我是个新手，大概2个月前刚开始学习Arduino（为了参加一个比赛），在极客工坊潜水很久，学习了很多东西，现在也想把这段时间学习的东西和大家分享。我看到论坛里关于无线发射模块的资料比较少，所以我来发一个无线方面的学习笔记，关于nRF24L01
关于无线模块大家比较熟悉的可能是APC220和Xbee这两种无线模块，网上的资料也很多，我也就不班门弄斧了，但这两种无线模块价格比较贵（因为这个比赛有一个要求是对成本的控制），所以我后来开始研究nRF24L01来进行2个Arduino板子之间的通讯（2块nRF24L01只有36块钱）
关于nRF24L01，工作于2.4 GHz～2.5 GHz ISM频段， 最高工作速率2Mbps，125 频道，满足多点通信和跳频通信需要，低功耗1.9 - 3.6V 工作，待机模式下状态为22uA；掉电模式下为900nA，可以用SPI控制
首先你需要有2块Arduino开发板和2块nRF24L01通信芯片，一个作为发射，一个作为接收。如果你使用的是标准的Arduino开发板，请注意使用开发板上的3.3V pin 作为电源，因为nRF24L01的工作电压是1.9~3.6V，如果使用5V的供电口会把nRF24L01芯片烧坏。
测试程序原文地址：http://www.elecfreaks.com/203.html
这个测试程序的接口如下：
GND – GND, VCC – 3.3V, CS – D8, CSN – D9, SCK – D10, MOSI – D11, MISO – D12, IRQ – D13
（IRQ这个口在这个例程中并没有用到，所以可以不接）
接好后的示意图如下：
这个测试程序是发射端不断发送0x00到0XFF的数据给接收端（程序中用到的头文件打包在附件里）
先是发射端的代码：/*********************************************************************
**Device:nRF24L01+ **
**File: EF_nRF24L01_TX.c **
** **
** **
**Copyright (C) 2011 ElecFraks. **
**This example code is in the public domain. **
** **
**Description: **
**This file is a sample code for your reference. **
**It's the v1.1 nRF24L01+ by arduino **
**Created by ElecFreaks. Robi.W,24 July 2011 **
** **
**http://www.elecfreaks.com **
** **
** SPI-compatible **
** CS - to digital pin 8 **
** CSN - to digital pin 9(SS pin) **
** SCK - to digital pin 10 (SCK pin) **
** MOSI - to digital pin 11 (MOSI pin) **
** MISO - to digital pin 12 (MISO pin) **
** IRQ - to digital pin 13 (MISO pin) **
*********************************************************************/
#include "NRF24L01.h"
//***************************************************
#define TX_ADR_WIDTH 5 // 5 unsigned chars TX(RX) address width
#define TX_PLOAD_WIDTH32// 32 unsigned chars TX payload
unsigned char TX_ADDRESS=
{
0x34,0x43,0x10,0x10,0x01
}; // Define a static TX address
unsigned char rx_buf = {0}; // initialize value
unsigned char tx_buf = {0};
//***************************************************
void setup()
{
pinMode(CE,OUTPUT);
pinMode(SCK, OUTPUT);
pinMode(CSN, OUTPUT);
pinMode(MOSI,OUTPUT);
pinMode(MISO, INPUT);
pinMode(IRQ, INPUT);
//attachInterrupt(1, _ISR, LOW);// interrupt enable
Serial.begin(9600);
init_io(); // Initialize IO port
unsigned char status=SPI_Read(STATUS);
Serial.print("status = ");
Serial.println(status,HEX); // There is read the mode鈥檚 status register, the default value should be 鈥楨鈥?Serial.println("*******************TX_Mode Start****************************");
TX_Mode(); // set TX mode
}
void loop()
{
int k = 0;
for(;;)
{
for(int i=0; i<32; i++)
tx_buf = k++;
unsigned char status = SPI_Read(STATUS); // read register STATUS's value
if(status&TX_DS) // if receive data ready (TX_DS) interrupt
{
SPI_RW_Reg(FLUSH_TX,0);
SPI_Write_Buf(WR_TX_PLOAD,tx_buf,TX_PLOAD_WIDTH); // write playload to TX_FIFO
}
if(status&MAX_RT) // if receive data ready (MAX_RT) interrupt, this is retransmit thanSETUP_RETR
{
SPI_RW_Reg(FLUSH_TX,0);
SPI_Write_Buf(WR_TX_PLOAD,tx_buf,TX_PLOAD_WIDTH); // disable standy-mode
}
SPI_RW_Reg(WRITE_REG+STATUS,status); // clear RX_DR or TX_DS or MAX_RT interrupt flag
delay(1000);
}
}
//**************************************************
// Function: init_io();
// Description:
// flash led one time,chip enable(ready to TX or RX Mode),
// Spi disable,Spi clock line init high
//**************************************************
void init_io(void)
{
digitalWrite(IRQ, 0);
digitalWrite(CE, 0); // chip enable
digitalWrite(CSN, 1); // Spi disable
}
/**************************************************
* Function: SPI_RW();
*
* Description:
* Writes one unsigned char to nRF24L01, and return the unsigned char read
* from nRF24L01 during write, according to SPI protocol
**************************************************/
unsigned char SPI_RW(unsigned char Byte)
{
unsigned char i;
for(i=0;i<8;i++) // output 8-bit
{
if(Byte&0x80)
{
digitalWrite(MOSI, 1);
}
else
{
digitalWrite(MOSI, 0);
}
digitalWrite(SCK, 1);
Byte <<= 1; // shift next bit into MSB..
if(digitalRead(MISO) == 1)
{
Byte |= 1; // capture current MISO bit
}
digitalWrite(SCK, 0);
}
return(Byte); // return read unsigned char
}
/**************************************************/
/**************************************************
* Function: SPI_RW_Reg();
*
* Description:
* Writes value 'value' to register 'reg'
/**************************************************/
unsigned char SPI_RW_Reg(unsigned char reg, unsigned char value)
{
unsigned char status;
digitalWrite(CSN, 0); // CSN low, init SPI transaction
status = SPI_RW(reg); // select register
SPI_RW(value); // ..and write value to it..
digitalWrite(CSN, 1); // CSN high again
return(status); // return nRF24L01 status unsigned char
}
/**************************************************/
/**************************************************
* Function: SPI_Read();
*
* Description:
* Read one unsigned char from nRF24L01 register, 'reg'
/**************************************************/
unsigned char SPI_Read(unsigned char reg)
{
unsigned char reg_val;
digitalWrite(CSN, 0); // CSN low, initialize SPI communication...
SPI_RW(reg); // Select register to read from..
reg_val = SPI_RW(0); // ..then read register value
digitalWrite(CSN, 1); // CSN high, terminate SPI communication
return(reg_val); // return register value
}
/**************************************************/
/**************************************************
* Function: SPI_Read_Buf();
*
* Description:
* Reads 'unsigned chars' #of unsigned chars from register 'reg'
* Typically used to read RX payload, Rx/Tx address
/**************************************************/
unsigned char SPI_Read_Buf(unsigned char reg, unsigned char *pBuf, unsigned char bytes)
{
unsigned char status,i;
digitalWrite(CSN, 0); // Set CSN low, init SPI tranaction
status = SPI_RW(reg); // Select register to write to and read status unsigned char
for(i=0;i<bytes;i++)
{
pBuf = SPI_RW(0); // Perform SPI_RW to read unsigned char from nRF24L01
}
digitalWrite(CSN, 1); // Set CSN high again
return(status); // return nRF24L01 status unsigned char
}
/**************************************************/
/**************************************************
* Function: SPI_Write_Buf();
*
* Description:
* Writes contents of buffer '*pBuf' to nRF24L01
* Typically used to write TX payload, Rx/Tx address
/**************************************************/
unsigned char SPI_Write_Buf(unsigned char reg, unsigned char *pBuf, unsigned char bytes)
{
unsigned char status,i;
digitalWrite(CSN, 0); // Set CSN low, init SPI tranaction
status = SPI_RW(reg); // Select register to write to and read status unsigned char
for(i=0;i<bytes; i++) // then write all unsigned char in buffer(*pBuf)
{
SPI_RW(*pBuf++);
}
digitalWrite(CSN, 1); // Set CSN high again
return(status); // return nRF24L01 status unsigned char
}
/**************************************************/
/**************************************************
* Function: TX_Mode();
*
* Description:
* This function initializes one nRF24L01 device to
* TX mode, set TX address, set RX address for auto.ack,
* fill TX payload, select RF channel, datarate & TX pwr.
* PWR_UP is set, CRC(2 unsigned chars) is enabled, & PRIM:TX.
*
* ToDo: One high pulse(>10us) on CE will now send this
* packet and expext an acknowledgment from the RX device.
**************************************************/
void TX_Mode(void)
{
digitalWrite(CE, 0);
SPI_Write_Buf(WRITE_REG + TX_ADDR, TX_ADDRESS, TX_ADR_WIDTH); // Writes TX_Address to nRF24L01
SPI_Write_Buf(WRITE_REG + RX_ADDR_P0, TX_ADDRESS, TX_ADR_WIDTH); // RX_Addr0 same as TX_Adr for Auto.Ack
SPI_RW_Reg(WRITE_REG + EN_AA, 0x01); // Enable Auto.Ack:Pipe0
SPI_RW_Reg(WRITE_REG + EN_RXADDR, 0x01);// Enable Pipe0
SPI_RW_Reg(WRITE_REG + SETUP_RETR, 0x1a); // 500us + 86us, 10 retrans...
SPI_RW_Reg(WRITE_REG + RF_CH, 40); // Select RF channel 40
SPI_RW_Reg(WRITE_REG + RF_SETUP, 0x07); // TX_PWR:0dBm, Datarate:2Mbps, LNA:HCURR
SPI_RW_Reg(WRITE_REG + CONFIG, 0x0e); // Set PWR_UP bit, enable CRC(2 unsigned chars) & Prim:TX. MAX_RT & TX_DS enabled..
SPI_Write_Buf(WR_TX_PLOAD,tx_buf,TX_PLOAD_WIDTH);
digitalWrite(CE, 1);
}
再是接收端的代码：
/*********************************************************************
**Device:nRF24L01+ **
**File: EF_nRF24L01_TX.c **
** **
** **
**Copyright (C) 2011 ElecFraks. **
**This example code is in the public domain. **
** **
**Description: **
**This file is a sample code for your reference. **
**It's the v1.1 nRF24L01+ by arduino **
**Created by ElecFreaks. Robi.W,24 July 2011 **
** **
**http://www.elecfreaks.com **
** **
** SPI-compatible **
** CS - to digital pin 8 **
** CSN - to digital pin 9(SS pin) **
** SCK - to digital pin 10 (SCK pin) **
** MOSI - to digital pin 11 (MOSI pin) **
** MISO - to digital pin 12 (MISO pin) **
** IRQ - to digital pin 13 (MISO pin) **
*********************************************************************/
#include "NRF24L01.h"
//***************************************************
#define TX_ADR_WIDTH 5 // 5 unsigned chars TX(RX) address width
#define TX_PLOAD_WIDTH32// 32 unsigned chars TX payload
unsigned char TX_ADDRESS=
{
0x34,0x43,0x10,0x10,0x01
}; // Define a static TX address
unsigned char rx_buf;
unsigned char tx_buf;
//***************************************************
void setup()
{
pinMode(CE,OUTPUT);
pinMode(SCK, OUTPUT);
pinMode(CSN, OUTPUT);
pinMode(MOSI,OUTPUT);
pinMode(MISO, INPUT);
pinMode(IRQ, INPUT);
//attachInterrupt(1, _ISR, LOW); // interrupt enable
Serial.begin(9600);
init_io(); // Initialize IO port
unsigned char status=SPI_Read(STATUS);
Serial.print("status = ");
Serial.println(status,HEX); // There is read the mode鈥檚 status register, the default value should be 鈥楨鈥?
Serial.println("*****************RX_Mode start******************************R");
RX_Mode(); // set RX mode
}
void loop()
{
for(;;)
{
unsigned char status = SPI_Read(STATUS); // read register STATUS's value
if(status&RX_DR) // if receive data ready (TX_DS) interrupt
{
SPI_Read_Buf(RD_RX_PLOAD, rx_buf, TX_PLOAD_WIDTH); // read playload to rx_buf
SPI_RW_Reg(FLUSH_RX,0); // clear RX_FIFO
for(int i=0; i<32; i++)
{
Serial.print(" ");
Serial.print(rx_buf,HEX); // print rx_buf
}
Serial.println(" ");
}
SPI_RW_Reg(WRITE_REG+STATUS,status); // clear RX_DR or TX_DS or MAX_RT interrupt flag
delay(1000);
}
}
//**************************************************
// Function: init_io();
// Description:
// flash led one time,chip enable(ready to TX or RX Mode),
// Spi disable,Spi clock line init high
//**************************************************
void init_io(void)
{
digitalWrite(IRQ, 0);
digitalWrite(CE, 0); // chip enable
digitalWrite(CSN, 1); // Spi disable
}
/**************************************************
* Function: SPI_RW();
*
* Description:
* Writes one unsigned char to nRF24L01, and return the unsigned char read
* from nRF24L01 during write, according to SPI protocol
**************************************************/
unsigned char SPI_RW(unsigned char Byte)
{
unsigned char i;
for(i=0;i<8;i++) // output 8-bit
{
if(Byte&0x80)
{
digitalWrite(MOSI, 1); // output 'unsigned char', MSB to MOSI
}
else
{
digitalWrite(MOSI, 0);
}
digitalWrite(SCK, 1); // Set SCK high..
Byte <<= 1; // shift next bit into MSB..
if(digitalRead(MISO) == 1)
{
Byte |= 1; // capture current MISO bit
}
digitalWrite(SCK, 0); // ..then set SCK low again
}
return(Byte); // return read unsigned char
}
/**************************************************/
/**************************************************
* Function: SPI_RW_Reg();
*
* Description:
* Writes value 'value' to register 'reg'
/**************************************************/
unsigned char SPI_RW_Reg(unsigned char reg, unsigned char value)
{
unsigned char status;
digitalWrite(CSN, 0); // CSN low, init SPI transaction
status = SPI_RW(reg); // select register
SPI_RW(value); // ..and write value to it..
digitalWrite(CSN, 1); // CSN high again
return(status); // return nRF24L01 status unsigned char
}
/**************************************************/
/**************************************************
* Function: SPI_Read();
*
* Description:
* Read one unsigned char from nRF24L01 register, 'reg'
/**************************************************/
unsigned char SPI_Read(unsigned char reg)
{
unsigned char reg_val;
digitalWrite(CSN, 0); // CSN low, initialize SPI communication...
SPI_RW(reg); // Select register to read from..
reg_val = SPI_RW(0); // ..then read register value
digitalWrite(CSN, 1); // CSN high, terminate SPI communication
return(reg_val); // return register value
}
/**************************************************/
/**************************************************
* Function: SPI_Read_Buf();
*
* Description:
* Reads 'unsigned chars' #of unsigned chars from register 'reg'
* Typically used to read RX payload, Rx/Tx address
/**************************************************/
unsigned char SPI_Read_Buf(unsigned char reg, unsigned char *pBuf, unsigned char bytes)
{
unsigned char status,i;
digitalWrite(CSN, 0); // Set CSN low, init SPI tranaction
status = SPI_RW(reg); // Select register to write to and read status unsigned char
for(i=0;i<bytes;i++)
{
pBuf = SPI_RW(0); // Perform SPI_RW to read unsigned char from nRF24L01
}
digitalWrite(CSN, 1); // Set CSN high again
return(status); // return nRF24L01 status unsigned char
}
/**************************************************/
/**************************************************
* Function: SPI_Write_Buf();
*
* Description:
* Writes contents of buffer '*pBuf' to nRF24L01
* Typically used to write TX payload, Rx/Tx address
/**************************************************/
unsigned char SPI_Write_Buf(unsigned char reg, unsigned char *pBuf, unsigned char bytes)
{
unsigned char status,i;
digitalWrite(CSN, 0); // Set CSN low, init SPI tranaction
status = SPI_RW(reg); // Select register to write to and read status unsigned char
for(i=0;i<bytes; i++) // then write all unsigned char in buffer(*pBuf)
{
SPI_RW(*pBuf++);
}
digitalWrite(CSN, 1); // Set CSN high again
return(status); // return nRF24L01 status unsigned char
}
/**************************************************/
/**************************************************
* Function: RX_Mode();
*
* Description:
* This function initializes one nRF24L01 device to
* RX Mode, set RX address, writes RX payload width,
* select RF channel, datarate & LNA HCURR.
* After init, CE is toggled high, which means that
* this device is now ready to receive a datapacket.
/**************************************************/
void RX_Mode(void)
{
digitalWrite(CE, 0);
SPI_Write_Buf(WRITE_REG + RX_ADDR_P0, TX_ADDRESS, TX_ADR_WIDTH); // Use the same address on the RX device as the TX device
SPI_RW_Reg(WRITE_REG + EN_AA, 0x01); // Enable Auto.Ack:Pipe0
SPI_RW_Reg(WRITE_REG + EN_RXADDR, 0x01);// Enable Pipe0
SPI_RW_Reg(WRITE_REG + RF_CH, 40); // Select RF channel 40
SPI_RW_Reg(WRITE_REG + RX_PW_P0, TX_PLOAD_WIDTH); // Select same RX payload width as TX Payload width
SPI_RW_Reg(WRITE_REG + RF_SETUP, 0x07); // TX_PWR:0dBm, Datarate:2Mbps, LNA:HCURR
SPI_RW_Reg(WRITE_REG + CONFIG, 0x0f); // Set PWR_UP bit, enable CRC(2 unsigned chars) & Prim:RX. RX_DR enabled..
digitalWrite(CE, 1); // Set CE pin high to enable RX device
//This device is now ready to receive one packet of 16 unsigned chars payload from a TX device sending to address
//'3443101001', with auto acknowledgment, retransmit count of 10, RF channel 40 and datarate = 2Mbps.
}
/**************************************************/
把程序分别烧进2块板子后，把发射端接一个9V的电源，接收端用USB连电脑，打开Arduino IDE 的串口监视器，就可以看到运行的结果：
本帖最后由 Randy 于 2012-7-20 16:27 编辑
潜水有罪，罚你看群一个月！{:soso_e117:}
帮忙贴出引脚定义：
CE：使能发射或接收;
CSN，SCK，MOSI，MISO：SPI引脚端，微处理器可通过此引脚配置nRF24L01：
IRQ：中断标志位;
VDD：电源输入端;
VSS：电源地：
XC2，XC1：晶体振荡器引脚;
VDD_PA：为功率放大器供电，输出为1.8 V;
ANT1,ANT2：天线接口;
IREF：参考电流输入。 好东西收下了 呵呵，学了2个月越来越觉得Arduino很有意思，也越来越觉得他的局限性 学习了，感谢分享，楼主的程序和注释写的真是很清晰，赞一个！ 哈哈，试过了，不错，穿一堵墙还能传输3米远，不过源代码还应加上#include <SPI.h>，才能编译通过:lol 请问，这个关于24L01的代码，不也是用软件模拟spi 吗，既然板子有spi接口，为什么不直接用spi库函数呢。 redlight 发表于 2012-6-22 10:59 static/image/common/back.gif
请问，这个关于24L01的代码，不也是用软件模拟spi 吗，既然板子有spi接口，为什么不直接用spi库函数呢。
对，你说的没错，这个代码是模仿SPI写的函数，可能直接套用SPI的库函数有些小地方不太匹配，作者就自己模仿SPI的函数写了一个，作者自己也说他的函数当中可能还有些不完善的地方，大家可以根据自己的需要再修改 :funk:后排围观 Muller_r 发表于 2012-6-22 12:18 static/image/common/back.gif
对，你说的没错，这个代码是模仿SPI写的函数，可能直接套用SPI的库函数有些小地方不太匹配，作者就自己模 ...
恩，好，我下到板子上 试一试。。。:) 程序没问题的，要是改成收发一体的就更好了 redlight 发表于 2012-6-22 20:09 static/image/common/back.gif
程序没问题的，要是改成收发一体的就更好了
应该是可以改的，就是要调整一下接口的状态，这个我到还没试过，我用nRF24L01的时候只是做了单向的通信 麻烦问下大家，我用的是一个mega2560和一个Arduino Duemilanove 328的板子，看楼主说GND – GND, VCC – 3.3V, CS – D8, CSN – D9, SCK – D10, MOSI – D11, MISO – D12, IRQ – D13，但是却没有任何效果，我怀疑是mega2560的引脚与Duemilanove的不一样，所以想问问大家怎么连接？？或者可没有可能是什么别的原因？？ 本帖最后由 pww999 于 2012-7-19 23:01 编辑
查查M 2560的引脚图就行了
2560 须修改这几个地方
记得我用2560是这样接的
//MISO -> D50
// * MOSI ->D51
// * SCK ->D52
//* CE ->D53
//* CSN ->D38
Muller_r 发表于 2012-6-23 12:45 static/image/common/back.gif
应该是可以改的，就是要调整一下接口的状态，这个我到还没试过，我用nRF24L01的时候只是做了单向的通信
我用的是两块2560板子做的实验，结果却是出乎意料的坏，看图！