xmpl_trx_txaret.c - Transmitting Frames with TX_ARET

Application Description

The example shows, how a frame is transmitted in TX_ARET mode. Within this mode, CCA is done automatically. Additionally the example illustrates, how the fram data can be directly manipulated in the SRAM (see IRQ service routine).

Code Example

/* $Id: pgXmplTrxTxAret.html,v 1.1.1.4 2013/04/09 21:12:16 awachtler Exp $ */
/* Example for transmitting frames in tx_aret mode */

#include "board.h"
#include "transceiver.h"
#include "ioutil.h"
#include "xmpl.h"

static volatile bool tx_in_progress;
static volatile uint8_t tx_cnt, fail_cnt;

#define SEQ_OFFSET     (2)
#define TX_FAIL_OFFSET (7)
#define TX_SRAM_OFFSET (1)

int main(void)
{
trx_regval_t rval;
uint8_t txfrm[] = {0x21,0x08,                /* IEEE 802.15.4 FCF: 
                                                data frame with ack request */
                   42,                       /* sequence counter */
                   (PANID & 0xff), (PANID >> 8), /* destination PAN_ID */
                   (SHORT_ADDR & 0xff), (SHORT_ADDR >> 8), /* dest. short address */
                   42,                       /* TX fail counter */
                   'h','e','l','l','o',' ','µ','r','a','c','o','l','i','!', /* data */
                   'X','X'    /* these bytes are overwritten from transceivers
                               * CRC generator directly before sent. */
                  };
    /* This will stop the application before initializing the radio transceiver
     * (ISP issue with MISO pin, see FAQ)
     */
    trap_if_key_pressed();

    /* Step 0: init MCU peripherals */
    LED_INIT();
    trx_io_init(SPI_RATE_1_2);
    LED_SET_VALUE(LED_MAX_VALUE);
    LED_SET_VALUE(0);

    /* Step 1: initialize the transceiver */
    TRX_RESET_LOW();
    TRX_SLPTR_LOW();
    DELAY_US(TRX_RESET_TIME_US);
    TRX_RESET_HIGH();
    trx_reg_write(RG_TRX_STATE,CMD_TRX_OFF);
    DELAY_MS(TRX_INIT_TIME_US);
    rval = trx_bit_read(SR_TRX_STATUS);
    ERR_CHECK(TRX_OFF!=rval);
    LED_SET_VALUE(1);

    /* Step 2: setup transmitter
     * - configure radio channel
     * - enable transmitters automatic crc16 generation
     * - go into TX state,
     * - enable "transmit end" IRQ
     */
    trx_bit_write(SR_CHANNEL,CHANNEL);
    trx_bit_write(SR_TX_AUTO_CRC_ON,1);
    trx_reg_write(RG_TRX_STATE,CMD_TX_ARET_ON);
#if defined(TRX_IRQ_TRX_END)
    trx_reg_write(RG_IRQ_MASK,TRX_IRQ_TRX_END);
#elif defined(TRX_IRQ_TX_END)
    trx_reg_write(RG_IRQ_MASK,TRX_IRQ_TX_END);
#else
#  error "Unknown IRQ bits"
#endif
    sei();
    LED_SET_VALUE(2);

    /* Step 3: send a frame each 500ms */
    tx_cnt = 0;
    tx_in_progress = false;
    LED_SET_VALUE(0);

    while(1)
    {
        WAIT500MS();
        if (tx_in_progress == false)
        {
            txfrm[SEQ_OFFSET] = tx_cnt;
            txfrm[TX_FAIL_OFFSET] = fail_cnt;
            trx_frame_write (sizeof(txfrm), txfrm);
            tx_in_progress = true;
            TRX_SLPTR_HIGH();
            TRX_SLPTR_LOW();
            LED_SET(1);
            LED_TOGGLE(0);
        }
    }
}

#if defined(TRX_IF_RFA1)
ISR(TRX24_TX_END_vect)
{
static volatile trx_regval_t trac_status;

    trac_status = trx_bit_read(SR_TRAC_STATUS);

    tx_in_progress = false;
    if (trac_status != TRAC_SUCCESS)
    {
        fail_cnt++;
    }
    else
    {
        tx_cnt ++;
        LED_CLR(1);
    }
}
#else  /* !RFA1 */
ISR(TRX_IRQ_vect)
{
static volatile trx_regval_t irq_cause;
static volatile trx_regval_t trac_status;

    irq_cause = trx_reg_read(RG_IRQ_STATUS);
    trac_status = trx_bit_read(SR_TRAC_STATUS);

    if (irq_cause & TRX_IRQ_TRX_END)
    {
        tx_in_progress = false;
        if (trac_status != TRAC_SUCCESS)
        {
            fail_cnt++;
        }
        else
        {
            tx_cnt ++;
            LED_CLR(1);
        }
    }
}
#endif  /* RFA1 */

/* EOF */