avr/morse_tx/main.c

#include <avr/io.h>
#include <util/delay.h>
#include <base.h>
#include <spi.h>

typedef struct RFM {
    spi_t spi;
    gpio_t irq;
    gpio_t reset;
} rfm_t;

void rfm_initialize(rfm_t *rfm) {
    spi_initialize(&rfm->spi);

    spi_acquire(&rfm->spi);
    spi_transfer_byte(&rfm->spi, 0x37 | _BV(7));
    spi_transfer_byte(&rfm->spi, 0);
    spi_release(&rfm->spi);

    spi_acquire(&rfm->spi);
    spi_transfer_byte(&rfm->spi, 0x38 | _BV(7));
    spi_transfer_byte(&rfm->spi, 1);
    spi_release(&rfm->spi);
}

void rfm_power_off(rfm_t *rfm) {
    spi_acquire(&rfm->spi);
    spi_transfer_byte(&rfm->spi, 0x11);
    spi_transfer_byte(&rfm->spi, 0x00);
    spi_release(&rfm->spi);
}

void rfm_send_data(rfm_t *rfm, uint8_t *data, size_t length) {
    /* Go into standby mode */
    spi_acquire(&rfm->spi);
    spi_transfer_byte(&rfm->spi, 0x11);
    spi_transfer_byte(&rfm->spi, 0x01);
    spi_release(&rfm->spi);

    /* Write data to FIFO */
    spi_acquire(&rfm->spi);
    spi_transfer_byte(&rfm->spi, 0x10);
    for (size_t i = 0; i < length; i++) {
        spi_transfer_byte(&rfm->spi, data[i]);
    }
    spi_release(&rfm->spi);

    /* Go into transmit mode */
    spi_acquire(&rfm->spi);
    spi_transfer_byte(&rfm->spi, 0x11);
    spi_transfer_byte(&rfm->spi, 0x03);
    spi_release(&rfm->spi);

    /* Return to standby mode */
    spi_acquire(&rfm->spi);
    spi_transfer_byte(&rfm->spi, 0x11);
    spi_transfer_byte(&rfm->spi, 0x01);
    spi_release(&rfm->spi);
}

int main(void) {
    spi_t spi = (spi_t){
        .clock          = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 1 },
        .data_out       = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 2 },
        .data_in        = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 3 },
        .chip_select    = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 4 },
    };

    rfm_t rfm = (rfm_t){
        .spi    = spi,
        .irq    = { .ddr = &DDRE, .port = &PORTE, .pin = &PINE, .addr = 6 },
        .reset  = { .ddr = &DDRD, .port = &PORTD, .pin = &PIND, .addr = 4 },
    };

    gpio_t light = { .ddr = &DDRC, .port = &PORTC, .addr = 7 };

    rfm_initialize(&rfm);

    uint8_t count[1] = { 0 };
    while(1) {
        rfm_send_data(&rfm, count, 1);
        count[0]++;
        set_line(&light);
        _delay_ms(50);
        clear_line(&light);
        _delay_ms(50);
    }
    return 0;
}