nrf24l01_radio.c

#include <ModmataC.h>
#include <ncurses.h>
 
#define IRQ 8
#define CE 9
#define CS 10
 
void printReg(char* name, uint8_t reg, int num_bytes) {
    uint8_t *write_buf = malloc(sizeof(uint8_t) * (num_bytes + 1));
    write_buf[0] = reg;
    for(int i = 0; i < num_bytes; i++) {
        write_buf[i+1] = 0xAA;
    }
    uint8_t *read_buf = spiTransferBuf(CS, write_buf, num_bytes + 1);
    
    printw("%s: ", name);
    for(int i = 0; i < num_bytes; i++) {
        printw("%02x ", read_buf[i+1]);
    }
    printw("\n");
 
    free(write_buf);
    free(read_buf);
}
 
void setTransmitMode(uint8_t my_addr, uint8_t their_addr, int debug) {
    uint8_t write_buf[6];
    uint8_t *read_buf;
 
    // SETUP_RETR Register
    // Set max delay and retransmits
    write_buf[0] = 0x04 | 0x20;
    write_buf[1] = 0xff;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // RF_SETUP Register
    // Set data rate to 250kbps at max power
    write_buf[0] = 0x06 | 0x20;
    write_buf[1] = 0x27;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // RF_PW_P0 Register
    // Set payload size on pipe 0 to 32 bytes
    write_buf[0] = 0x11 | 0x20;
    write_buf[1] = 0x20;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // RF_PW_P1 Register
    // Set payload size on pipe 1 to 32 bytes
    write_buf[0] = 0x12 | 0x20;
    write_buf[1] = 0x20;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // EN_AA Register
    // Set auto-acknowledgement on receive pipes
    write_buf[0] = 0x01 | 0x20;
    write_buf[1] = 0x03;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // EN_RXADDR Register
    // Enable receive pipes
    write_buf[0] = 0x02 | 0x20;
    write_buf[1] = 0x03;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // CONFIG Register
    // Set transmit mode and 2-byte CRC's
    write_buf[0] = 0x00 | 0x20;
    write_buf[1] = 0x0e;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // RF_CH Register
    // Set frequency channel to 2.476 GHz
    write_buf[0] = 0x05 | 0x20;
    write_buf[1] = 0x4c;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // TX_ADDR Register
    // Set to receiver address
    write_buf[0] = 0x10 | 0x20;
    for (int i = 1; i < 6; i++) {
        write_buf[i] = their_addr;
    }
    read_buf = spiTransferBuf(CS, write_buf, 6);
    free(read_buf);
 
    // RX_ADDR_P0 Register
    // Set to receiver address
    write_buf[0] = 0x0a | 0x20;
    read_buf = spiTransferBuf(CS, write_buf, 6);
    free(read_buf);
 
    // RX_ADDR_P1 Register
    // Set to own address
    write_buf[0] = 0x0b | 0x20;
    for (int i = 1; i < 6; i++) {
        write_buf[i] = my_addr;
    }
    read_buf = spiTransferBuf(CS, write_buf, 6);
    free(read_buf);
 
    // STATUS Register
    // Clear current status
    write_buf[0] = 0x07 | 0x20;
    write_buf[1] = 0x7e;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    if(debug) {
        printReg("SETUP_RETR", 0x04, 1);
        printReg("RF_SETUP", 0x06, 1);
        printReg("RF_PW_P0", 0x11, 1);
        printReg("RF_PW_P1", 0x12, 1);
        printReg("EN_AA", 0x01, 1);
        printReg("EN_RXADDR", 0x02, 1);
        printReg("CONFIG", 0x00, 1);
        printReg("RF_CH", 0x05, 1);
        printReg("TX_ADDR", 0x10, 5);
        printReg("RX_ADDR_P0", 0x0a, 5);
        printReg("RX_ADDR_P1", 0x0b, 5);
        printReg("STATUS", 0x07, 1);
    }
}
 
void setReceiveMode(uint8_t my_addr, int debug) {
    uint8_t write_buf[6];
    uint8_t *read_buf;
 
    // SETUP_RETR Register
    // Set max delay and retransmits
    write_buf[0] = 0x04 | 0x20;
    write_buf[1] = 0xff;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // RF_SETUP Register
    // Set data rate to 250kbps at max power
    write_buf[0] = 0x06 | 0x20;
    write_buf[1] = 0x27;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // RF_PW_P0 Register
    // Set payload size on pipe 0 to 32 bytes
    write_buf[0] = 0x11 | 0x20;
    write_buf[1] = 0x20;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // RF_PW_P1 Register
    // Set payload size on pipe 1 to 32 bytes
    write_buf[0] = 0x12 | 0x20;
    write_buf[1] = 0x20;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // EN_AA Register
    // Set auto-acknowledgement on receive pipes
    write_buf[0] = 0x01 | 0x20;
    write_buf[1] = 0x03;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // EN_RXADDR Register
    // Enable receive pipes
    write_buf[0] = 0x02 | 0x20;
    write_buf[1] = 0x03;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
    
    // CONFIG Register
    // Set receive mode and 2-byte CRC's
    write_buf[0] = 0x00 | 0x20;
    write_buf[1] = 0x0f;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // RF_CH Register
    // Set frequency channel to 2.476 GHz
    write_buf[0] = 0x05 | 0x20;
    write_buf[1] = 0x4c;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    // TX_ADDR Register
    // Set to own address
    write_buf[0] = 0x10 | 0x20;
    for (int i = 1; i < 6; i++) {
        write_buf[i] = my_addr;
    }
    read_buf = spiTransferBuf(CS, write_buf, 6);
    free(read_buf);
 
    // RX_ADDR_P0 Register
    // Set to own address
    write_buf[0] = 0x0a | 0x20;
    read_buf = spiTransferBuf(CS, write_buf, 6);
    free(read_buf);
 
    // RX_ADDR_P1 Register
    // Set to own address
    write_buf[0] = 0x0b | 0x20;
    read_buf = spiTransferBuf(CS, write_buf, 6);
    free(read_buf);
 
    // STATUS
    // Clear status register
    write_buf[0] = 0x07 | 0x20;
    write_buf[1] = 0x7e;
    read_buf = spiTransferBuf(CS, write_buf, 2);
    free(read_buf);
 
    if (debug) {
        printReg("SETUP_RETR", 0x04, 1);
        printReg("RF_SETUP", 0x06, 1);
        printReg("RF_PW_P0", 0x11, 1);
        printReg("RF_PW_P1", 0x12, 1);
        printReg("EN_AA", 0x01, 1);
        printReg("EN_RXADDR", 0x02, 1);
        printReg("CONFIG", 0x00, 1);
        printReg("RF_CH", 0x05, 1);
        printReg("TX_ADDR", 0x10, 5);
        printReg("RX_ADDR_P0", 0x0a, 5);
        printReg("RX_ADDR_P1", 0x0b, 5);
        printReg("STATUS", 0x7e, 1);
    }
}
 
int main() {
    // start serial connection with arduino, given a port, baud rate, and id
    connectArduino("/dev/ttyACM0", 115200, 1);
    
    // Set up chip enable pins for SPI
    pinMode(CS, OUTPUT);
    pinMode(CE, OUTPUT);
    pinMode(IRQ, INPUT);
    digitalWrite(CS, HIGH);
    digitalWrite(CE, HIGH);
    
    // Start up SPI library
    spiBegin();
 
    // Start ncurses
    initscr();
    scrollok(stdscr, 1);
    
    // Set addresses for users
    int my_addr = -1;
    printw("Choose your device address (0-255): ");
    scanw("%d", &my_addr);
    while (my_addr < 0 || my_addr > 255) {
        printw("Invalid address!\n");
        printw("Choose your device address (0-255): ");
        scanw("%d", &my_addr);
    }
    
    int their_addr = -1;
    printw("Enter a device address to communicate with (0-255): ");
    scanw("%d", &their_addr);
    while(their_addr < 0 || their_addr > 255) {
        printw("Invalid address!\n");
        printw("Enter a device address to communicate with (0-255): ");
        scanw("%d", &their_addr);
    }
 
    // Power on the nrf24
    digitalWrite(CE, LOW);
    delay(100);
    
    // Set all the registers to receive messages
    setReceiveMode(my_addr, 0);
    
    // Enter receive mode
    digitalWrite(CE, HIGH);
    delayMicroseconds(140);
    
    
    char str[33] = {0x00};
    // char *s = str;
    // size_t str_size = 32;
    char c;
    while(1) {
        // printReg("STATUS", 0x07, 1);
        nodelay(stdscr, 1);
        c = getch();
        if (c == 0x0A) {
            nodelay(stdscr, 0);
            printw("> ");
            getnstr(str, 32);
            
            // Switch to transmit mode
            digitalWrite(CE, LOW);
            setTransmitMode(my_addr, their_addr, 0);
            digitalWrite(CE, HIGH);
            delayMicroseconds(140);
            
            // Set up buffers for byte transfers
            uint8_t wr_buf[33] = {0x00};
            uint8_t *read_buf;
 
            // Clear TX FIFO
            wr_buf[0] = 0xE1;
            read_buf = spiTransferBuf(CS, wr_buf, 1);
            free(read_buf);
            
            // Clear RX FIFO
            wr_buf[0] = 0xE2;
            read_buf = spiTransferBuf(CS, wr_buf, 1);
            free(read_buf);
            
            // Queue up the message
            wr_buf[0] = 0xA0;
            for (int i = 0; str[i] != 0x00; i++) { // This should work right?
                wr_buf[i+1] = str[i];
            }
            read_buf = spiTransferBuf(CS, wr_buf, 33);
            free(read_buf);
            
            // Wait for message to send (IRQ goes low)
            while(digitalRead(IRQ));
            
            /*
            // Check for ACK from receiver
            wr_buf[0] = 0x07;
            read_buf = spiTransferBuf(CS, wr_buf, 2);
            if((read_buf[1] & 0x20) == 0x20) {
                // printf("Message sent!\n");
            }
            else if ((read_buf[1] & 0x10) == 0x10) {
                printw("No ACK received :(\n");
            }
            else {
                printw("Unknown error: %02x\n", read_buf[1]);
            }
            free(read_buf);
            */
 
            // Clear TX FIFO again
            wr_buf[0] = 0xE1;
            read_buf = spiTransferBuf(CS, wr_buf, 1);
            free(read_buf);
 
            // Switch back to receive mode
            digitalWrite(CE, LOW);
            setReceiveMode(my_addr, 0);
            digitalWrite(CE, HIGH);
            delayMicroseconds(140);
        }
            
        // Check for received message
        if (!digitalRead(IRQ)) {
            // printf("Message available!\n");
            uint8_t write_buf[33];
            uint8_t *read_buf;
            
            // Flush TX FIFO
            write_buf[0] = 0xE1;
            read_buf = spiTransferBuf(CS, write_buf, 1);
            free(read_buf);
 
            // R_RX_PAYLOAD
            printw("< ");
            write_buf[0] = 0x61;
            read_buf = spiTransferBuf(CS, write_buf, 33);
            for (int i = 0; i < 32; i++) {
                printw("%c", read_buf[i+1]);
            }
            printw("\n");
            free(read_buf);
 
            // Flush RX FIFO
            write_buf[0] = 0xE2;
            read_buf = spiTransferBuf(CS, write_buf, 1);
            free(read_buf);
 
            // Clear STATUS Register
            write_buf[0] = 0x07 | 0x20;
            write_buf[1] = 0x7E;
            read_buf = spiTransferBuf(CS, write_buf, 2);
            free(read_buf);
        }
    }
    
    // Close ncurses window 
    endwin();
 
    // Disconnect modmata
    closeConnection();  
}