1
0
Fork 0
mirror of https://github.com/betaflight/betaflight.git synced 2025-07-15 04:15:44 +03:00
betaflight/src/main/drivers/rx_nrf24l01.c
2017-05-26 14:03:28 +01:00

250 lines
7.5 KiB
C

/*
* This file is part of Cleanflight.
*
* Cleanflight is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Cleanflight is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Cleanflight. If not, see <http://www.gnu.org/licenses/>.
*/
// This file is copied with modifications from project Deviation,
// see http://deviationtx.com
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <platform.h>
#ifdef USE_RX_NRF24
#include "build/build_config.h"
#include "drivers/bus_spi.h"
#include "drivers/io.h"
#include "drivers/io_impl.h"
#include "drivers/rx_spi.h"
#include "drivers/rx_nrf24l01.h"
#include "drivers/time.h"
#define NRF24_CE_HI() {IOHi(DEFIO_IO(RX_CE_PIN));}
#define NRF24_CE_LO() {IOLo(DEFIO_IO(RX_CE_PIN));}
// Instruction Mnemonics
// nRF24L01: Table 16. Command set for the nRF24L01 SPI. Product Specification, p46
// nRF24L01+: Table 20. Command set for the nRF24L01+ SPI. Product Specification, p51
#define R_REGISTER 0x00
#define W_REGISTER 0x20
#define REGISTER_MASK 0x1F
#define ACTIVATE 0x50
#define R_RX_PL_WID 0x60
#define R_RX_PAYLOAD 0x61
#define W_TX_PAYLOAD 0xA0
#define W_ACK_PAYLOAD 0xA8
#define FLUSH_TX 0xE1
#define FLUSH_RX 0xE2
#define REUSE_TX_PL 0xE3
#define NOP 0xFF
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();
}
uint8_t NRF24L01_WriteReg(uint8_t reg, uint8_t data)
{
return rxSpiWriteCommand(W_REGISTER | (REGISTER_MASK & reg), data);
}
uint8_t NRF24L01_WriteRegisterMulti(uint8_t reg, const uint8_t *data, uint8_t length)
{
return rxSpiWriteCommandMulti(W_REGISTER | ( REGISTER_MASK & reg), data, length);
}
/*
* Transfer the payload to the nRF24L01 TX FIFO
* Packets in the TX FIFO are transmitted when the
* nRF24L01 next enters TX mode
*/
uint8_t NRF24L01_WritePayload(const uint8_t *data, uint8_t length)
{
return rxSpiWriteCommandMulti(W_TX_PAYLOAD, data, length);
}
uint8_t NRF24L01_WriteAckPayload(const uint8_t *data, uint8_t length, uint8_t pipe)
{
return rxSpiWriteCommandMulti(W_ACK_PAYLOAD | (pipe & 0x07), data, length);
}
uint8_t NRF24L01_ReadReg(uint8_t reg)
{
return rxSpiReadCommand(R_REGISTER | (REGISTER_MASK & reg), NOP);
}
uint8_t NRF24L01_ReadRegisterMulti(uint8_t reg, uint8_t *data, uint8_t length)
{
return rxSpiReadCommandMulti(R_REGISTER | (REGISTER_MASK & reg), NOP, data, length);
}
/*
* Read a packet from the nRF24L01 RX FIFO.
*/
uint8_t NRF24L01_ReadPayload(uint8_t *data, uint8_t length)
{
return rxSpiReadCommandMulti(R_RX_PAYLOAD, NOP, data, length);
}
/*
* Empty the transmit FIFO buffer.
*/
void NRF24L01_FlushTx(void)
{
rxSpiWriteByte(FLUSH_TX);
}
/*
* Empty the receive FIFO buffer.
*/
void NRF24L01_FlushRx(void)
{
rxSpiWriteByte(FLUSH_RX);
}
uint8_t NRF24L01_Activate(uint8_t code)
{
return rxSpiWriteCommand(ACTIVATE, code);
}
// standby configuration, used to simplify switching between RX, TX, and Standby modes
static uint8_t standbyConfig;
void NRF24L01_Initialize(uint8_t baseConfig)
{
standbyConfig = BV(NRF24L01_00_CONFIG_PWR_UP) | baseConfig;
NRF24L01_InitGpio();
// 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
}
/*
* Common setup of registers
*/
void NRF24L01_SetupBasic(void)
{
NRF24L01_WriteReg(NRF24L01_01_EN_AA, 0x00); // No auto acknowledgment
NRF24L01_WriteReg(NRF24L01_02_EN_RXADDR, BV(NRF24L01_02_EN_RXADDR_ERX_P0));
NRF24L01_WriteReg(NRF24L01_03_SETUP_AW, NRF24L01_03_SETUP_AW_5BYTES); // 5-byte RX/TX address
NRF24L01_WriteReg(NRF24L01_1C_DYNPD, 0x00); // Disable dynamic payload length on all pipes
}
/*
* 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);
}
/*
* 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_ClearAllInterrupts(void)
{
// Writing to the STATUS register clears the specified interrupt bits
NRF24L01_WriteReg(NRF24L01_07_STATUS, BV(NRF24L01_07_STATUS_RX_DR) | BV(NRF24L01_07_STATUS_TX_DS) | BV(NRF24L01_07_STATUS_MAX_RT));
}
void NRF24L01_SetChannel(uint8_t channel)
{
NRF24L01_WriteReg(NRF24L01_05_RF_CH, channel);
}
bool NRF24L01_ReadPayloadIfAvailable(uint8_t *data, uint8_t length)
{
if (NRF24L01_ReadReg(NRF24L01_17_FIFO_STATUS) & BV(NRF24L01_17_FIFO_STATUS_RX_EMPTY)) {
return false;
}
NRF24L01_ReadPayload(data, length);
return true;
}
#ifndef UNIT_TEST
#define DISABLE_RX() {IOHi(DEFIO_IO(RX_NSS_PIN));}
#define ENABLE_RX() {IOLo(DEFIO_IO(RX_NSS_PIN));}
/*
* Fast read of payload, for use in interrupt service routine
*/
bool NRF24L01_ReadPayloadIfAvailableFast(uint8_t *data, uint8_t length)
{
// number of bits transferred = 8 * (3 + length)
// for 16 byte payload, that is 8*19 = 152
// at 50MHz clock rate that is approximately 3 microseconds
bool ret = false;
ENABLE_RX();
rxSpiTransferByte(R_REGISTER | (REGISTER_MASK & NRF24L01_07_STATUS));
const uint8_t status = rxSpiTransferByte(NOP);
if ((status & BV(NRF24L01_07_STATUS_RX_DR)) == 0) {
ret = true;
// clear RX_DR flag
rxSpiTransferByte(W_REGISTER | (REGISTER_MASK & NRF24L01_07_STATUS));
rxSpiTransferByte(BV(NRF24L01_07_STATUS_RX_DR));
rxSpiTransferByte(R_RX_PAYLOAD);
for (uint8_t i = 0; i < length; i++) {
data[i] = rxSpiTransferByte(NOP);
}
}
DISABLE_RX();
return ret;
}
#endif // UNIT_TEST
#endif // USE_RX_NRF24