//Handyboard NRF24L01 Interface
//Rand Voorhies

#define nordic_ce 7 
#define nordic_csn 6
#define spi_sck 5
#define spi_mosi 4
#define spi_miso 7
#define irq 8

void up_tone() {
    tone(440., .1); tone(660., .1); tone(880., .1); tone(1320., .1);   
}
void down_tone() {
    tone(880., .1); tone(660., .1); tone(440., .1); tone(220., .1);
}

void spi_xmit(int c[], int c_size, int csn) {
    int i,j;
    
    clear_digital_out(csn);
    
    for(j=0;j<c_size;j++) {
        for(i=0;i<8;i++) {
            
            //output the high bit on the mosi line
            if(c[j] & 0b10000000)
              set_digital_out(spi_mosi);
            else
              clear_digital_out(spi_mosi);
            
            //Raise the clock
            set_digital_out(spi_sck);
            
            //left shift in the miso data
            c[j] = (c[j] << 1) | (~digital(spi_miso) & 0b00000001);
            
            //lower the clock
            clear_digital_out(spi_sck);
        }
    }
    
    set_digital_out(csn);   
}

void nordic_reset_irq() {
    int send_buffer[2];
    
    //Write to the STATUS register:
    //Clear all of the IRQ bits
    send_buffer[0] = 0x27;
    send_buffer[1] = 0x70;
    spi_xmit(send_buffer,2,nordic_csn);
}


int nordic_init() {
    
    int c = 0;
    int send_buffer[2];
    
    set_digital_out(nordic_csn);
    clear_digital_out(spi_sck);
    clear_digital_out(nordic_ce);
    
    //Write to the RX_PW_P0 Register
    //Set the Data Pipe 0 to have a 1 byte payload size
    send_buffer[0] = 0x31;
    send_buffer[1] = 0x01;
    spi_xmit(send_buffer,2,nordic_csn);
    
    //Write to the CONFIG register:
    //Turn on 1-bit CRC, Set the Device in RX Mode, Turn Off TX_DS and MAX_RT, and Power UP!
    send_buffer[0] = 0x20;
    send_buffer[1] = 0x3B;
    spi_xmit(send_buffer,2,nordic_csn);
    
    //Verify that the COMMAND register was written properly
    send_buffer[0] = 0x00;
    send_buffer[1] = 0x00;
    spi_xmit(send_buffer,2,nordic_csn);
    
    set_digital_out(nordic_ce);
    
    if(send_buffer[1] == 0x3B) {
        printf("\nNordic Unit     Initialized!");
        up_tone();
        return 0x01;
    }
    else {     
        printf("\nNordic Unit Not Initialized!");
        down_tone();
        return 0x00;
    }
    sleep(.5);    
    nordic_reset_irq();
}


int nordic_transmit(int message[], int size) {
    int send_buffer[2];
    int message_buffer[33];
    int i;
    
    //Prepend the W_TX_PAYLOAD command to the messsage
    message_buffer[0] = 0xA0;
    for(i=0; i<size; i++)
      message_buffer[i+1] = message[i];   
    
    
    //Write to the CONFIG register:
    //Set the device in TX-mode
    send_buffer[0] = 0x20;
    send_buffer[1] = 0x0A;
    spi_xmit(send_buffer,2,nordic_csn);
    
    clear_digital_out(nordic_ce);
    
    //Clock in the payload
    spi_xmit(message_buffer, size+1, nordic_csn);
    
    //Pulse CE for >=10uS
    set_digital_out(nordic_ce);
    sleep(.1);
    clear_digital_out(nordic_ce);
    
    //Write to the CONFIG register:
    //Put the device back into RX-mode
    send_buffer[0] = 0x20;
    send_buffer[1] = 0x0B;
    spi_xmit(send_buffer,2,nordic_csn);
    
    set_digital_out(nordic_ce);
}

int nordic_get_rx_buffer(int message[], int size) {
    int buffer[33];
    int i;
    
    buffer[0] = 0x61;
    clear_digital_out(nordic_ce);
    spi_xmit(buffer, size+1, nordic_csn);
    set_digital_out(nordic_ce);
    
    for(i=0;i<size;i++)
      message[i] = buffer[i+1];
    
    //If the RX buffer is empty, then reset the interrupt
    if(message[0] &= 0x01) {
        message[0] = 0x27;
        message[1] = 
    }
}



void nordic_set_message_size(int pipe, int size) {
    
    int send_buffer[2];
    
    if(pipe < 0 || pipe > 5) {
        down_tone();
        printf("\nError - Bad Pipe # (%d)!\n", pipe);
        while(1);
    }
    if(size < 0 || size > 32) {
        down_tone();
        printf("\nError - Bad Msg Size(%d)!\n", size);
        while(1);
    }    
    
    send_buffer[0] = 0x31 + pipe;
    send_buffer[1] = size;
    spi_xmit(send_buffer,2,nordic_csn);   
}