wayne roberts / Mbed OS alarm_slave

raises pin at time instructed by received LoRa packet.

Dependencies:   sx126x sx12xx_hal

radio chip selection

Radio chip driver is not included, allowing choice of radio device.
If you're using SX1272 or SX1276, then import sx127x driver into your program.
if you're using SX1261 or SX1262, then import sx126x driver into your program.
if you're using SX1280, then import sx1280 driver into your program.
If you're using NAmote72 or Murata discovery, then you must import only sx127x driver.

Transmitter side is at Alarm Slave project page.
Output is observed on nucleo morpho connector pins pin[A-D]: see code for actual pins used.

main.cpp

Committer:
Wayne Roberts
Date:
2018-07-18
Revision:
3:f81d64ff0164
Parent:
2:bf201940a9db

File content as of revision 3:f81d64ff0164:

#include "radio.h"
 
DigitalOut myled(LED1);

#if defined(SX127x_H) || defined(SX126x_H)
    #define BW_KHZ              500
    #define SPREADING_FACTOR    11
    #define CF_HZ               910800000
#elif defined(SX128x_H)
    #define BW_KHZ              200
    #define SPREADING_FACTOR    11
    #define CF_HZ               2487000000
#endif

#ifdef TARGET_DISCO_L072CZ_LRWAN1
    DigitalOut pinA(PB_12);
    DigitalOut pinB(PB_13);
    DigitalOut pinC(PB_14);
    DigitalOut pinD(PB_15);
#else
    DigitalOut pinA(PC_3);
    DigitalOut pinB(PC_2);
    DigitalOut pinC(PC_6);
    DigitalOut pinD(PC_8);
#endif /* !TARGET_DISCO_L072CZ_LRWAN1 */

DigitalOut* pin; 
Timeout to;

#define PIN_ASSERT_us       500000

#define CMD_PINA       0x02
#define CMD_PINB       0x03
#define CMD_PINC       0x06
#define CMD_PIND       0x08

/**********************************************************************/

void alarm_pin_clr()
{
    pin->write(0);
}

void alarm_pin_set()
{
    pin->write(1);
    to.attach_us(&alarm_pin_clr, PIN_ASSERT_us);
}

static uint16_t crc_ccitt( uint8_t *buffer, uint16_t length )
{
    // The CRC calculation follows CCITT
    const uint16_t polynom = 0x1021;
    // CRC initial value
    uint16_t crc = 0x0000;

    if( buffer == NULL )
    {
        return 0;
    }

    for( uint16_t i = 0; i < length; ++i )
    {
        crc ^= ( uint16_t ) buffer[i] << 8;
        for( uint16_t j = 0; j < 8; ++j )
        {
            crc = ( crc & 0x8000 ) ? ( crc << 1 ) ^ polynom : ( crc << 1 );
        }
    }

    return crc;
}

void get_alarm()
{
    uint16_t rx_crc, crc = crc_ccitt(Radio::radio.rx_buf, 5);
    rx_crc = Radio::radio.rx_buf[5];
    rx_crc <<= 8;
    rx_crc += Radio::radio.rx_buf[6];
    //printf("%u) crc rx:%04x, calc:%04x\r\n", lora.RegRxNbBytes, rx_crc, crc);
    if (crc == rx_crc) {
        uint8_t c = Radio::radio.rx_buf[0];
        if (c == CMD_PINA || c == CMD_PINB || c == CMD_PINC || c == CMD_PIND) {
            unsigned delay;
            delay = Radio::radio.rx_buf[1];
            delay <<= 8;
            delay += Radio::radio.rx_buf[2];
            delay <<= 8;
            delay += Radio::radio.rx_buf[3];
            delay <<= 8;
            delay += Radio::radio.rx_buf[4];
            switch (c) {
                case CMD_PINA: pin = &pinA; break;
                case CMD_PINB: pin = &pinB; break;
                case CMD_PINC: pin = &pinC; break;
                case CMD_PIND: pin = &pinD; break;
            }
            to.attach_us(&alarm_pin_set, delay);
            printf("delay:%u\r\n", delay);
        } else
            printf("cmd? %02x\r\n", Radio::radio.rx_buf[0]);
    } else
        printf("crc fail %04x, %04x\r\n", rx_crc, crc);
}

void txDoneCB()
{
}

void rxDoneCB(uint8_t size, float Rssi, float Snr)
{
    get_alarm();
    printf("%.1fdBm  snr:%.1fdB ", Rssi, Snr);
}

const RadioEvents_t rev = {
    /* Dio0_top_half */     NULL,
    /* TxDone_topHalf */    NULL,
    /* TxDone_botHalf */    txDoneCB,
    /* TxTimeout  */        NULL,
    /* RxDone  */           rxDoneCB,
    /* RxTimeout  */        NULL,
    /* RxError  */          NULL,
    /* FhssChangeChannel  */NULL,
    /* CadDone  */          NULL
};

 
int main()
{   
    printf("\r\nreset-rx\r\n");


    Radio::Init(&rev);

    Radio::Standby();
    Radio::LoRaModemConfig(BW_KHZ, SPREADING_FACTOR, 1);
    Radio::LoRaPacketConfig(8, false, true, false);  // preambleLen, fixLen, crcOn, invIQ
    Radio::SetChannel(CF_HZ);
    
    Radio::Rx(0);
    
    for (;;) {     
        Radio::service();
    }
}