LowPowerLab Forum

Hardware support => RF - Range - Antennas - RFM69 library => Topic started by: Ttech on December 15, 2013, 07:50:01 AM

Title: RFM69 RX Configuration
Post by: Ttech on December 15, 2013, 07:50:01 AM
Hi ,

I am trying to write my own code to get RFM69 into RX mode and want to recive  large packets over 433Mhz  .
My question is what sequence to follow , e.g
After i send all the base parameters to RFM69 via SPI like : Bit rate setting , Frequency deviation , RX Bandwidth , Carrier frequency,
Preamble, Sync values and Payload lenght .

I then map DIO pins to sense Payload ready on DIO0 and then read FIFO .

Although i have confirmed my TX is working as its fires off Packet send , but RX does not toggle Pay load ready ???

Do i have to wait for a certain time to sense Payload Ready signal ???


Title: Re: RFM69 RX Configuration
Post by: Felix on December 15, 2013, 10:54:47 AM
Are you trying to write your own library?
Have you seen how it's done in my library?
Title: Re: RFM69 RX Configuration
Post by: Ttech on December 16, 2013, 12:11:03 AM
Hi Felix ,

Yes i am writing my library or function , its for PIC microcontroller .

See the code below :

int i;
RxLed = 1;
TxLed = 0;
SpiWriteByte(RegDIOMap1, 0x44);   // DIO0=Payload Ready
SpiWriteByte(RegFIFOThresh, PKLENGTH+7);
SpiWriteByte(RegOpMode, OM_RX);   // RX Mode
SysTime = 0;
  if (SpiReadByte(RegIRQFlag1)&0x80);   //Rx mode ready
     printf("\n\r RX Mode = Ready");
    if(nIRQ) // DIO0=Payload Ready
              /// RX Ready , Now read data ///////////////
           BurstRead(RegFIFO, RxData, PKLENGTH+7);
              RxLed = 0;   
              SpiWriteByte(RegOpMode, OM_STANDBY);
               RxLed = 1;
               printf("\n\r IRQ not detected");

Title: Re: RFM69 RX Configuration
Post by: Felix on December 16, 2013, 07:43:42 AM
The send/receive routines are quite different. There are a lot of things you have to set just right before it will work. Both radios have to have the exact same settings (mostly). The datasheet will be helpful in determining what these params are. I would point you to my library rather than try to explain what needs to be done. I think the code is pretty self explanatory and besides that I don't recall all the register values and all the settings. I will just say that it's a finely tuned assembly of code (think fragile) that took some time to get right and even a missing register can make the whole thing work partially or not at all.
Title: Re: RFM69 RX Configuration
Post by: Ttech on December 17, 2013, 12:09:10 AM
Hi Felix ,

Thanks for your reply , can you direct me to a particular file where you have followed that sequence in your library .

HopeRF gave me an example and they are settiing these base parameters to configure RFM69 :

const word RFM69ConfigTbl[20] = {
 0x0200,        //RegDataModul : Packet Mode, FSK, No Shaping   
 0x0502,        //RegFdevMsb      241*61Hz = 35KHz   
 0x0641,        //RegFdevLsb
 0x0334,        //RegBitrateMsb      32MHz/0x3410 = 2.4kpbs
 0x0410,        //RegBitrateLsb
 0x130F,        //RegOcp         Disable OCP
 0x1888,        //RegLNA            200R   
 0x1952,        //RegRxBw         RxBW  83KHz
 0x2C00,        //RegPreambleMsb   
 0x2D05,        //RegPreambleLsb   5Byte Preamble
 0x2E90,        //enable Sync.Word   2+1=3bytes
 0x2FAA,        //0xAA            SyncWord = aa2dd4
 0x302D,        //0x2D
 0x31D4,        //0xD4
 0x3700,        //RegPacketConfig1  Disable CRC£¬NRZ encode
 0x3815,        //RegPayloadLength  21bytes for length & Fixed length
 0x3C95,        //RegFiFoThresh      
 0x581B,        //RegTestLna        Normal sensitivity
 //0x582D,        //RegTestLna        increase sensitivity with LNA (Note: consumption also increase!)
 0x6F30,        //RegTestDAGC       Improved DAGC
 //0x6F00,        //RegTestDAGC       Normal DAGC
 0x0104,        // RegOpMode = Standby   
/// <<<<<< RX Entry parameters >>>>> /////
const word RFM69RxTable[5] = {           
 0x119F,        //RegPaLevel : Pa0=0n, Pa1 and Pa2=off, Pout=11111
 0x2544,        //DIO Mapping for Rx : DIO0=Payload Ready, DIO1=Fifo level   
 0x5A55,        //RegTestPa1=Normal mode and Rx mode
 0x5C70,        //RegTestPa2=Normal mode and Rx mode      
 0x0110,        //RegOpMode=RX mode
///// <<< TX Entry Parameters >>> /////
const word RFM69TxTable[5] = {
 0x2504,        //
 0x119F,        //RegPaLevel 13dBm
 0x5A55,        //Normal and TRx
 0x5C70,        //Normal and TRx   
 0x010C,        //Entry to Tx mode

Title: Re: RFM69 RX Configuration
Post by: A on December 17, 2013, 12:55:58 AM
Check out these three files:


Your "const word RFM69ConfigTbl[20]" lines up fairly closely with Felix's "bool RFM69::initialize(byte freqBand, byte nodeID, byte networkID)" in RFM69.cpp.
Title: Re: RFM69 RX Configuration
Post by: Ttech on December 17, 2013, 07:32:54 AM
Hi A ,

Thanks for the link to RFM69.cpp

I must admit i am new to this coding , therefore i am asking for help from you or anyone to explain a few lines

e.g this is sending all base parameters :

 for (byte i = 0; CONFIG[0] != 255; i++)
    writeReg(CONFIG[0], CONFIG[1]);

And over here we are entering RX mode :

  case RF69_MODE_RX:
                        writeReg(REG_OPMODE, (readReg(REG_OPMODE) & 0xE3) | RF_OPMODE_RECEIVER);

And here it is sensing if Payload Ready is high :

void RFM69::interruptHandler() {
  //pinMode(4, OUTPUT);
  //digitalWrite(4, 1);
  if (_mode == RF69_MODE_RX && (readReg(REG_IRQFLAGS2) & RF_IRQFLAGS2_PAYLOADREADY))
    SPI.transfer(REG_FIFO & 0x7f);
    PAYLOADLEN = SPI.transfer(0);
    PAYLOADLEN = PAYLOADLEN > 66 ? 66 : PAYLOADLEN; //precaution
    TARGETID = SPI.transfer(0);
    if(!(_promiscuousMode || TARGETID==_address || TARGETID==0)) //match this node's address, or broadcast addr 0x0 or anything in promiscuous mode
      PAYLOADLEN = 0;
      //digitalWrite(4, 0);

Am i right ?
Title: Re: RFM69 RX Configuration
Post by: Felix on December 17, 2013, 08:22:57 AM
I think you got it. Keep in mind that whole piece of code represents a state machine that goes in/out of different states depending on a few factors. By default the radio will be in RX mode and the interrupt will service any receptions and fill the buffers. The user should then periodically check if something was received using the receiveDone() function and empty the buffers (otherwise buffers get overwritten when new packets arrive). Everything you need is in the 2 files that A linked.
Title: Re: RFM69 RX Configuration
Post by: Ttech on December 18, 2013, 08:57:40 AM
Hi Felix,

I tried to clean up code and put it the way it is written in RFM69Registers.h but my TX has stopped working , so here's is my main() routine :

 void main(void)
InitSfr();   // To initialize my special function registers of PIC         
InitPort(); //  To initialize IO ports of PIC
ChkSel(); // to check selection
for(SysTime=0; SysTime<26; ) // Creating a POR delay

    SetRfm(); // Base parameters for RFM69
    RCCalStart(); // a routine to check if the oscillator has locked
    TestTxMode(); // TX routine


Here's SetRfm()

void SetRfm(void)
        SpiWriteByte(RegDataModul, DM_FSK+DM_PH_MODE);   //FSK and Packet mode
//       SpiWriteByte(RegDataModul, DM_OOK+DM_PH_MODE);   //OOK and Packet mode
        //Frequency Dev                                                      
      SpiWriteByte(RegFdevMsb, 0x01);         //18KHz                 
      SpiWriteByte(RegFdevLsb, 0x27);               
        // Bit rate              
      SpiWriteByte(RegBitRateMsb, 0x68);      //1.2   
      SpiWriteByte(RegBitRateLsb, 0x2B);      
        SpiWriteByte(RegOcp,0x0f);   // Ocp Off
        SpiWriteByte(0x5a,0x55);   // RegTestPa1=off
        SpiWriteByte(0x5c,0x70);   // RegTestPa2=off
        // RX Sensitivity
        SpiWriteByte(RegLNA, 0x1B); // LNA setting
      SpiWriteByte(RegRxBW, 0x4C); //25K
        SpiWriteByte(RegPreambleMsb, 0x00);
        SpiWriteByte(RegPreambleLsb, 0x05);      //0xAA*5
        BurstWrite(RegSyncValue, SyncTable, 2);   
        SpiWriteByte(RegPacketConfig1, PH_VAR+PH_NRZ+PH_CRC_OFF); 
        //Payload Length 
        SpiWriteByte(RegPayloadLength, PKLENGTH+7);   
        SpiWriteByte(RegFIFOThresh, PKLENGTH+7); 
       //Carrier Freq
        BurstWrite(RegFreqMsb, FreqTable[FreqSel], 3); // For 433Mhz : 0x6C,0x80,0x00
        SpiWriteByte(RegTestLNA,0x1B); //RegTestLna:Normal sensitivity
        // TX Power
        SpiWriteByte(RegPaLevel, 0x8E); // Odbm

Here's the listing for RCCalStart

void RCCalStart(void)
 byte tmp;   
 SpiWriteByte(RegOpMode, OM_STANDBY); //STANDBY mode, Address RegOpMode=0x01
 SpiWriteByte(RegOsc1, 0x81); //RegOSC1=Address'0x0A', 0x81=RC Oscillator Calibration start
        //for(SysTime=0; SysTime<1; )
          for(SysTime=0; SysTime<9;)   
          tmp = SpiReadByte(RegOsc1);//Reading RC Osc calibration status 
   while(tmp!=0x41); //Check if RC Osc calibration over

And here's the main TX listing :

void TestTxMode (void)
 byte tmp;
 byte i;   
 RxLed = 0;
 TxLed = 1;   
 // Setting base parameters
 tmp = SpiReadByte(RegIRQFlag2); // Address RegIRQFlag2=0x28
 tmp |= 0x40;
 SpiWriteByte(RegIRQFlag2, tmp);   // FIFO
 SpiWriteByte(RegOpMode, OM_TX);
 for(SysTime=0; SysTime<35; )
 // Checking TX ready and Mode
 while((SpiReadByte(RegIRQFlag1)&0xA0)!=0xA0) ; //Status OK?
 SpiWriteByte(RegDIOMap1, 0x24); //GIO0 PacketSend/ GIO1 FIFONotEmpty/ GIO2 Data
 BurstWrite(RegFIFO, TxFiFoData, 57);      //Send first Packet   
SysTime = 0;
           if(SysTime>=40)         //OverTime   
      TxLed = 0;            
        SpiWriteByte(RegOpMode, OM_STANDBY);   
      for(SysTime=0; SysTime<5; )


Here's the listing for the interrupt based counter
void TimerQuery(void)
   TMR0_7 = 0;    


Can you take a look and point why TX is not working


Title: Re: RFM69 RX Configuration
Post by: Felix on December 18, 2013, 05:20:56 PM
I would be really at a loss to try to guess my way through the code.
Here's why:
So given this I'm afraid I cannot help.
Title: Re: RFM69 RX Configuration
Post by: Ttech on December 19, 2013, 05:19:55 AM
Hi Felix ,

I think you are right , its the same with me , as i cantt understand fully how your code is working .
But you can help understand the sequence in which to configure RFM69 so that it works .


Step 1 : there should be Power-on-Reset delay before any config data is send i.e 10ms

Step 2 : send all the base parameters i.e 1. Mode and Modualtion
                                                                  2. Frequency deviation
                                                                  3. Bit rate
                                                                  4. Over-current protection
                                                                  5. TestPa1 & 2
                                                                  6. LNA
                                                                  7. Rx BW
                                                                  8. Preamble
                                                                  9. Sync Value
                                                                  10.   Packet Config1
                                                                  11. Payload lenght
                                                                  12. Fifo Threshold
                                                                  13. Carrier Freq
                                                                  14. TestLNA
                                                                  15. TestDagc
                                                                  16. PaLevel

Step 3: 1. set RFM69 in standby mode
             2. Start RC Oscillator Calibration
             3. Check if it locked

Step 4: 1. set RFM69 in TX mode
             2. Wait for a few millisecs
             3. Read IRQFlag1 and confirm Mode ready
             4. Write data into Fifo to be Transmitted 
             5. Map DIO pins
             6. Sense Packet Sense
             7. set RFM69 in standby mode
             8. Wait for a few millisecs
             9. Loop back

If you think i am missing any step let me know

Regards ,
Title: Re: RFM69 RX Configuration
Post by: pmetty on April 28, 2014, 01:38:09 PM
Ttech - did you get your pic library working?  I'm starting a project with this transceiver and a PIC18 or PIC32.