µracoli Manual Version foo

- µracoli
- User Guide
- Reference Guide

xmpl_trx_echo.c

This example shows, how frames are received and retransmitted if their CRC was correct. This example is esentially a combination from pgXmplTrxTx and pgXmplTrxRx. The retransmission of the frames is initiated within the transceiver interrupt routine without any CCA.

Note
  Use this example with care !!! You can mess up your sensor network easily.

/* Copyright (c) 2009 Axel Wachtler
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of the authors nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE. */
/* $Id$ */
/* Example for echoing received frames */
#include "board.h"
#include "transceiver.h"
#include "ioutil.h"
#include <util/crc16.h>
#include "xmpl.h"
static uint8_t rxfrm[MAX_FRAME_SIZE];
static volatile uint8_t rxcnt;
static uint8_t state;
int main(void)
{
trx_regval_t rval;
mcu_init();
/* 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_US(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
* - go into RX state,
* - enable "receive end" IRQ
*/
trx_bit_write(SR_CHANNEL,CHANNEL);
trx_reg_write(RG_TRX_STATE,CMD_RX_ON);
#if defined(TRX_IRQ_TRX_END)
trx_reg_write(RG_IRQ_MASK,TRX_IRQ_TRX_END);
#elif defined(TRX_IRQ_RX_END) && defined(TRX_IRQ_TX_END)
trx_reg_write(RG_IRQ_MASK,TRX_IRQ_RX_END | TRX_IRQ_TX_END);
#else
# error "Unknown IRQ bits"
#endif
MCU_IRQ_ENABLE();
LED_SET_VALUE(2);
/* Step 3: Going to receive frames */
rxcnt = 0;
LED_SET_VALUE(0);
while(1);
}
#if defined(TRX_IF_RFA1)
ISR(TRX24_RX_END_vect)
{
uint8_t *pfrm, tmp, flen;
uint16_t crc;
LED_SET_VALUE(0);
/* upload frame and check for CRC16 validity */
pfrm = rxfrm;
flen = trx_frame_read(pfrm, sizeof(rxfrm), NULL);
tmp = flen;
crc = 0;
do
{
crc = _crc_ccitt_update(crc, *pfrm++);
}
while(tmp--);
/* if crc is correct, update RX frame counter */
if (crc == 0)
{
rxcnt ++;
/* echo the frame if CRC is valid*/
trx_reg_write(RG_TRX_STATE,CMD_FORCE_TRX_OFF);
trx_reg_write(RG_TRX_STATE,CMD_PLL_ON);
/*invert sequence number, just to show if it is from pinger */
rxfrm[2] ^=0xff;
DELAY_US(16); /* wait 1 symbol, XXX check this timing */
TRX_SLPTR_HIGH();
TRX_SLPTR_LOW();
trx_frame_write(flen,rxfrm);
state = STATE_TX;
}
/* display current frame count */
LED_SET_VALUE(rxcnt);
}
ISR(TRX24_TX_END_vect)
{
trx_reg_write(RG_TRX_STATE,CMD_RX_ON);
state = STATE_RX;
}
#else /* !RFA1 */
ISR(TRX_IRQ_vect)
{
static volatile trx_regval_t irq_cause;
uint8_t *pfrm, tmp, flen;
uint16_t crc;
irq_cause = trx_reg_read(RG_IRQ_STATUS);
if (irq_cause & TRX_IRQ_TRX_END)
{
if (state == STATE_TX)
{
trx_reg_write(RG_TRX_STATE,CMD_RX_ON);
state = STATE_RX;
}
else
{
LED_SET_VALUE(0);
/* upload frame and check for CRC16 validity */
pfrm = rxfrm;
flen = trx_frame_read(pfrm, sizeof(rxfrm), NULL);
tmp = flen;
crc = 0;
do
{
crc = _crc_ccitt_update(crc, *pfrm++);
}
while(tmp--);
/* if crc is correct, update RX frame counter */
if (crc == 0)
{
rxcnt ++;
/* echo the frame if CRC is valid*/
trx_reg_write(RG_TRX_STATE,CMD_FORCE_TRX_OFF);
trx_reg_write(RG_TRX_STATE,CMD_PLL_ON);
/*invert sequence number, just to show if it is from pinger */
rxfrm[2] ^=0xff;
DELAY_US(16); /* wait 1 symbol, XXX check this timing */
TRX_SLPTR_HIGH();
TRX_SLPTR_LOW();
trx_frame_write(flen,rxfrm);
state = STATE_TX;
}
/* display current frame count */
LED_SET_VALUE(rxcnt);
}
}
}
#endif /* RFA1 */
/* EOF */