/* @description reads the upper 8 bits of the status
* register (the interrupt flags)
*/
static uint8_t rfm12_read_int_flags_inline(void) {
#if !(RFM12_SPI_SOFTWARE)
SS_ASSERT();
SPDR = 0;
while (!(SPSR & (1<<SPIF)));
SS_RELEASE();
return SPDR;
#else
SS_ASSERT();
unsigned char x, d = d;
PORT_MOSI &= ~(1<<BIT_MOSI);
for (x = 0; x < 8; x++) {
PORT_SCK |= (1<<BIT_SCK);
d <<= 1;
if (PIN_MISO & (1<<BIT_MISO)) {
d |= 1;
}
PORT_SCK &= ~(1<<BIT_SCK);
}
SS_RELEASE();
return d;
#endif
}
//non-inlined version of rfm12_data
//warning: without the attribute, gcc will inline this even if -Os is set
static void __attribute__ ((noinline)) rfm12_data(uint16_t d) {
SS_ASSERT();
#if !(RFM12_SPI_SOFTWARE)
SPDR = d >> 8;
while (!(SPSR & (1<<SPIF)));
SPDR = d & 0xff;
while (!(SPSR & (1<<SPIF)));
#else
spi_data(d >> 8);
spi_data(d & 0xff);
#endif
SS_RELEASE();
}
//non-inlined version of rfm12_read
//warning: without the attribute, gcc will inline this even if -Os is set
static uint16_t __attribute__ ((noinline)) rfm12_read(uint16_t c) {
uint16_t retval;
SS_ASSERT();
#if !(RFM12_SPI_SOFTWARE)
SPDR = c >> 8;
while (!(SPSR & (1<<SPIF)));
retval = SPDR << 8;
SPDR = c & 0xff;
while (!(SPSR & (1<<SPIF)));
retval |= SPDR;
#else
retval = spi_data(c >> 8);
retval <<= 8;
retval |= spi_data(c & 0xff);
#endif
SS_RELEASE();
return retval;
}
/**This function takes care of all module initialization, including:
* - Setup of the used frequency band and external capacitor
* - Setting the exact frequency (channel)
* - Setting the transmission data rate
* - Configuring various module related rx parameters, including the amplification
* - Enabling the digital data filter
* - Enabling the use of the modules fifo, as well as enabling sync pattern detection
* - Configuring the automatic frequency correction
* - Setting the transmit power
*
* This initialization function also sets up various library internal configuration structs and
* puts the module into receive mode before returning.
*
* \note Please note that the transmit power and receive amplification values are currently hard coded.
* Have a look into rfm12_hw.h for possible settings.
*/
void rfm12_init(void)
{
RFM12_INT_OFF(); // in case rfm12_init is called twice, make sure rfm module does not interfere
//initialize spi
SS_RELEASE();
DDR_SS |= (1<<BIT_SS);
spi_init();
//enable internal data register and fifo
//setup selected band
rfm12_data(RFM12_CMD_CFG | RFM12_CFG_EL | RFM12_CFG_EF | RFM12_BASEBAND | RFM12_XTAL_12PF);
//set power default state (usually disable clock output)
//do not write the power register two times in a short time
//as it seems to need some recovery
rfm12_data(RFM12_CMD_PWRMGT | PWRMGT_DEFAULT);
//set frequency
rfm12_data(RFM12_CMD_FREQUENCY | RFM12_FREQUENCY_CALC(FREQ) );
//set data rate
rfm12_data(RFM12_CMD_DATARATE | DATARATE_VALUE );
//set rx parameters: int-in/vdi-out pin is vdi-out,
//Bandwith, LNA, RSSI
rfm12_data(RFM12_CMD_RXCTRL | RFM12_RXCTRL_P16_VDI
| RFM12_RXCTRL_VDI_FAST | RFM12_RXCTRL_BW_400 | RFM12_RXCTRL_LNA_6
| RFM12_RXCTRL_RSSI_79 );
//automatic clock lock control(AL), digital Filter(!S),
//Data quality detector value 3, slow clock recovery lock
rfm12_data(RFM12_CMD_DATAFILTER | RFM12_DATAFILTER_AL | 3);
//2 Byte Sync Pattern, Start fifo fill when sychron pattern received,
//disable sensitive reset, Fifo filled interrupt at 8 bits
rfm12_data(RFM12_CMD_FIFORESET | RFM12_FIFORESET_DR | (8<<4));
//set AFC to automatic, (+4 or -3)*2.5kHz Limit, fine mode, active and enabled
rfm12_data(RFM12_CMD_AFC | RFM12_AFC_AUTO_KEEP | RFM12_AFC_LIMIT_4
| RFM12_AFC_FI | RFM12_AFC_OE | RFM12_AFC_EN);
//set TX Power to -0dB, frequency shift = +-125kHz
rfm12_data(RFM12_CMD_TXCONF | RFM12_TXCONF_POWER_0 | RFM12_TXCONF_FS_CALC(125000) );
//disable low dutycycle mode
rfm12_data(RFM12_CMD_DUTYCYCLE);
//disable wakeup timer
rfm12_data(RFM12_CMD_WAKEUP);
//store the syncronization pattern to the transmission buffer
//the sync pattern is used by the receiver to distinguish noise from real transmissions
//the sync pattern is hardcoded into the receiver
rf_tx_buffer.sync[0] = SYNC_MSB;
rf_tx_buffer.sync[1] = SYNC_LSB;
//if receive mode is not disabled (default)
#if !(RFM12_TRANSMIT_ONLY)
//init buffer pointers
ctrl.rf_buffer_out = &rf_rx_buffers[0];
ctrl.rf_buffer_in = &rf_rx_buffers[0];
//ctrl.buffer_in_num = 0;
//ctrl.buffer_out_num = 0;
#endif /* !(RFM12_TRANSMIT_ONLY) */
//low battery detector feature initialization
#if RFM12_LOW_BATT_DETECTOR
ctrl.low_batt = RFM12_BATT_OKAY;
#endif /* RFM12_LOW_BATT_DETECTOR */
//enable rf receiver chain, if receiving is not disabled (default)
//the magic is done via defines
rfm12_data(RFM12_CMD_PWRMGT | PWRMGT_RECEIVE);
//wakeup timer feature setup
#if RFM12_USE_WAKEUP_TIMER
//set power management shadow register to receiver chain enabled or disabled
//the define correctly handles the transmit only mode
ctrl.pwrmgt_shadow = (RFM12_CMD_PWRMGT | PWRMGT_RECEIVE);
#endif /* RFM12_USE_WAKEUP_TIMER */
//ASK receive mode feature initialization
#if RFM12_RECEIVE_ASK
adc_init();
#endif
//setup interrupt for falling edge trigger
RFM12_INT_SETUP();
//clear int flag
rfm12_read(RFM12_CMD_STATUS);
RFM12_INT_FLAG |= (1<<RFM12_FLAG_BIT);
//init receiver fifo, we now begin receiving.
rfm12_data(CLEAR_FIFO);
rfm12_data(ACCEPT_DATA);
//activate the interrupt
RFM12_INT_ON();
}
