static void NRF24L01_InitGpio(void)
{
// CE as OUTPUT
const SPIDevice rxSPIDevice = spiDeviceByInstance(RX_SPI_INSTANCE);
IOInit(DEFIO_IO(RX_CE_PIN), OWNER_RX_SPI_CS, rxSPIDevice + 1);
IOConfigGPIO(DEFIO_IO(RX_CE_PIN), SPI_IO_CS_CFG);
NRF24_CE_LO();
}
/*
* Enter receive mode
*/
void NRF24L01_SetRxMode(void)
{
NRF24_CE_LO(); // drop into standby mode
// set the PRIM_RX bit
NRF24L01_WriteReg(NRF24L01_00_CONFIG, standbyConfig | BV(NRF24L01_00_CONFIG_PRIM_RX));
NRF24L01_ClearAllInterrupts();
// finally set CE high to start enter RX mode
NRF24_CE_HI();
// nRF24L01+ will now transition from Standby mode to RX mode after 130 microseconds settling time
}
/*
* Enter transmit mode. Anything in the transmit FIFO will be transmitted.
*/
void NRF24L01_SetTxMode(void)
{
// Ensure in standby mode, since can only enter TX mode from standby mode
NRF24L01_SetStandbyMode();
NRF24L01_ClearAllInterrupts();
// pulse CE for 10 microseconds to enter TX mode
NRF24_CE_HI();
delayMicroseconds(10);
NRF24_CE_LO();
// nRF24L01+ will now transition from Standby mode to TX mode after 130 microseconds settling time.
// Transmission will then begin and continue until TX FIFO is empty.
}
void NRF24L01_Initialize(uint8_t baseConfig)
{
standbyConfig = BV(NRF24L01_00_CONFIG_PWR_UP) | baseConfig;
NRF24_CE_LO();
// nRF24L01+ needs 100 milliseconds settling time from PowerOnReset to PowerDown mode
static const uint32_t settlingTimeUs = 100000;
const uint32_t currentTimeUs = micros();
if (currentTimeUs < settlingTimeUs) {
delayMicroseconds(settlingTimeUs - currentTimeUs);
}
// now in PowerDown mode
NRF24L01_WriteReg(NRF24L01_00_CONFIG, standbyConfig); // set PWR_UP to enter Standby mode
// nRF24L01+ needs 4500 microseconds from PowerDown mode to Standby mode, for crystal oscillator startup
delayMicroseconds(4500);
// now in Standby mode
}
/*
* Enter standby mode
*/
void NRF24L01_SetStandbyMode(void)
{
// set CE low and clear the PRIM_RX bit to enter standby mode
NRF24_CE_LO();
NRF24L01_WriteReg(NRF24L01_00_CONFIG, standbyConfig);
}
