nrf24.c

/*

* 

* ----------------------------------------------------------------------------

* “THE COFFEEWARE LICENSE” (Revision 1):

* <ihsan@kehribar.me> wrote this file. As long as you retain this notice you

* can do whatever you want with this stuff. If we meet some day, and you think

* this stuff is worth it, you can buy me a coffee in return.

* -----------------------------------------------------------------------------

* This library is based on this library: 

*   https://github.com/aaronds/arduino-nrf24l01

* Which is based on this library: 

*   http://www.tinkerer.eu/AVRLib/nRF24L01

* -----------------------------------------------------------------------------

*/

#include "nrf24.h"

uint8_t payload_len;

/* init the hardware pins */

void nrf24_init() 

{

  DDRB |= ((1<<CSN)|(1<<CE));

    wl_module_CE_lo;

    wl_module_CSN_hi; 

  spi_init(); 

}

/* configure the module */

void nrf24_config(uint8_t channel, uint8_t pay_length)//(2,4)

{

    /* Use static payload length ... */

    payload_len = pay_length;

    // Set RF channel

    nrf24_configRegister(RF_CH,channel);

    // Set length of incoming payload 

    nrf24_configRegister(RX_PW_P0, 0x00); // Auto-ACK pipe ...

    nrf24_configRegister(RX_PW_P1, payload_len); // Data payload pipe

    nrf24_configRegister(RX_PW_P2, 0x00); // Pipe not used 

    nrf24_configRegister(RX_PW_P3, 0x00); // Pipe not used 

    nrf24_configRegister(RX_PW_P4, 0x00); // Pipe not used 

    nrf24_configRegister(RX_PW_P5, 0x00); // Pipe not used 

    // 1 Mbps, TX gain: 0dbm

    nrf24_configRegister(RF_SETUP, (0<<RF_DR)|((0x03)<<RF_PWR));

    // CRC enable, 1 byte CRC length

    nrf24_configRegister(CONFIG,nrf24_CONFIG);

    // Auto Acknowledgment

    nrf24_configRegister(EN_AA,(1<<ENAA_P0)|(1<<ENAA_P1)|(0<<ENAA_P2)|(0<<ENAA_P3)|(0<<ENAA_P4)|(0<<ENAA_P5));

    // Enable RX addresses

    nrf24_configRegister(EN_RXADDR,(1<<ERX_P0)|(1<<ERX_P1)|(0<<ERX_P2)|(0<<ERX_P3)|(0<<ERX_P4)|(0<<ERX_P5));

    // Auto retransmit delay: 1000 us and Up to 15 retransmit trials

    nrf24_configRegister(SETUP_RETR,(0x04<<ARD)|(0x0F<<ARC));

    // Dynamic length configurations: No dynamic length

    nrf24_configRegister(DYNPD,(0<<DPL_P0)|(0<<DPL_P1)|(0<<DPL_P2)|(0<<DPL_P3)|(0<<DPL_P4)|(0<<DPL_P5));

    // Start listening

    nrf24_powerUpRx();

}

/* Set the RX address */

void nrf24_rx_address(uint8_t * adr) 

{

    wl_module_CE_lo;

    nrf24_writeRegister(RX_ADDR_P1,adr,nrf24_ADDR_LEN);

    wl_module_CE_hi;

}

/* Returns the payload length */

uint8_t nrf24_payload_length()

{

    return payload_len;

}

/* Set the TX address */

void nrf24_tx_address(uint8_t* adr)

{

    /* RX_ADDR_P0 must be set to the sending addr for auto ack to work. */

    nrf24_writeRegister(RX_ADDR_P0,adr,nrf24_ADDR_LEN);

    nrf24_writeRegister(TX_ADDR,adr,nrf24_ADDR_LEN);

}

/* Checks if data is available for reading */

/* Returns 1 if data is ready ... */

uint8_t nrf24_dataReady() 

{

    // See note in getData() function - just checking RX_DR isn't good enough

    uint8_t status = nrf24_getStatus();

    // We can short circuit on RX_DR, but if it's not set, we still need

    // to check the FIFO for any pending packets

    if ( status & (1 << RX_DR) ) 

    {

        return 1;

    }

    return !nrf24_rxFifoEmpty();;

}

/* Checks if receive FIFO is empty or not */

uint8_t nrf24_rxFifoEmpty()

{

    uint8_t fifoStatus;

    nrf24_readRegister(FIFO_STATUS,&fifoStatus,1);

    return (fifoStatus & (1 << RX_EMPTY));

}

/* Returns the length of data waiting in the RX fifo */

uint8_t nrf24_payloadLength()

{

    uint8_t status;

    wl_module_CSN_lo;

    spi_fast_shift(R_RX_PL_WID);

    status = spi_fast_shift(0x00);

    wl_module_CSN_hi;

    return status;

}

/* Reads payload bytes into data array */

void nrf24_getData(uint8_t* data) 

{

    /* Pull down chip select */

    wl_module_CSN_lo;                               

    /* Send cmd to read rx payload */

    spi_fast_shift( R_RX_PAYLOAD );

    /* Read payload */

    spi_transfer_sync(data,data,payload_len);

    /* Pull up chip select */

    wl_module_CSN_hi;

    /* Reset status register */

    nrf24_configRegister(STATUS,(1<<RX_DR));   

}

/* Returns the number of retransmissions occured for the last message */

uint8_t nrf24_retransmissionCount()

{

    uint8_t rv;

    nrf24_readRegister(OBSERVE_TX,&rv,1);

    rv = rv & 0x0F;

    return rv;

}

// Sends a data package to the default address. Be sure to send the correct

// amount of bytes as configured as payload on the receiver.

void nrf24_send(uint8_t* value) 

{    

    /* Go to Standby-I first */

    wl_module_CE_lo;

    /* Set to transmitter mode , Power up if needed */

    nrf24_powerUpTx();

    /* Do we really need to flush TX fifo each time ? */

    #if 1

        /* Pull down chip select */

        wl_module_CSN_lo;           

        /* Write cmd to flush transmit FIFO */

        spi_fast_shift(FLUSH_TX);     

        /* Pull up chip select */

        wl_module_CSN_hi;                    

    #endif 

    /* Pull down chip select */

    wl_module_CSN_lo;

    /* Write cmd to write payload */

    spi_fast_shift(W_TX_PAYLOAD);

    /* Write payload */

    spi_transmit_sync(value,payload_len);   

    /* Pull up chip select */

    wl_module_CSN_hi;

    /* Start the transmission */

    wl_module_CE_hi    

}

uint8_t nrf24_isSending()

{

    uint8_t status;

    /* read the current status */

    status = nrf24_getStatus();

    /* if sending successful (TX_DS) or max retries exceded (MAX_RT). */

    if((status & ((1 << TX_DS)  | (1 << MAX_RT))))

    {        

        return 0; /* false */

    }

    return 1; /* true */

}

uint8_t nrf24_getStatus()

{

    uint8_t rv;

    wl_module_CSN_lo;

    rv = spi_fast_shift(NOP);

    wl_module_CSN_hi;

    return rv;

}

uint8_t nrf24_lastMessageStatus()

{

    uint8_t rv;

    rv = nrf24_getStatus();

    /* Transmission went OK */

    if((rv & ((1 << TX_DS))))

    {

        return NRF24_TRANSMISSON_OK;

    }

    /* Maximum retransmission count is reached */

    /* Last message probably went missing ... */

    else if((rv & ((1 << MAX_RT))))

    {

        return NRF24_MESSAGE_LOST;

    }  

    /* Probably still sending ... */

    else

    {

        return 0xFF;

    }

}

void nrf24_powerUpRx()

{     

    wl_module_CSN_lo;

    spi_fast_shift(FLUSH_RX);

    wl_module_CSN_hi;

    nrf24_configRegister(STATUS,(1<<RX_DR)|(1<<TX_DS)|(1<<MAX_RT)); 

    wl_module_CE_lo;   

    nrf24_configRegister(CONFIG,nrf24_CONFIG|((1<<PWR_UP)|(1<<PRIM_RX)));    

    wl_module_CE_hi

}

void nrf24_powerUpTx()

{

    nrf24_configRegister(STATUS,(1<<RX_DR)|(1<<TX_DS)|(1<<MAX_RT)); 

    nrf24_configRegister(CONFIG,nrf24_CONFIG|((1<<PWR_UP)|(0<<PRIM_RX)));

}

void nrf24_powerDown()

{

    wl_module_CE_lo;

    nrf24_configRegister(CONFIG,nrf24_CONFIG);

}

/* Clocks only one byte into the given nrf24 register */

void nrf24_configRegister(uint8_t reg, uint8_t value)

{

    wl_module_CSN_lo;

    spi_fast_shift(W_REGISTER | (REGISTER_MASK & reg));

    spi_fast_shift(value);

    wl_module_CSN_hi;

}

/* Read single register from nrf24 */

void nrf24_readRegister(uint8_t reg, uint8_t* value, uint8_t len)

{

    wl_module_CSN_lo;

    spi_fast_shift(R_REGISTER | (REGISTER_MASK & reg));

    spi_transfer_sync(value,value,len);

    wl_module_CSN_hi;

}

/* Write to a single register of nrf24 */

void nrf24_writeRegister(uint8_t reg, uint8_t* value, uint8_t len) 

{

    wl_module_CSN_lo;

    spi_fast_shift(W_REGISTER | (REGISTER_MASK & reg));

    spi_transmit_sync(value,len);

    wl_module_CSN_hi;

}