Optimized high speed nRF24L01+ driver class documentation  v1.3.12
TMRh20 2020 - Optimized fork of the nRF24L01+ driver
Protected Member Functions | List of all members
RF24 Class Reference

Driver class for nRF24L01(+) 2.4GHz Wireless Transceiver. More...

#include <RF24.h>

Public Member Functions

Primary public interface

These are the main methods you need to operate the chip

 RF24 (uint16_t _cepin, uint16_t _cspin, uint32_t _spispeed=RF24_SPI_SPEED)
 
bool begin (void)
 
bool isChipConnected ()
 
void startListening (void)
 
void stopListening (void)
 
bool available (void)
 
void read (void *buf, uint8_t len)
 
bool write (const void *buf, uint8_t len)
 
void openWritingPipe (const uint8_t *address)
 
void openReadingPipe (uint8_t number, const uint8_t *address)
 
Deprecated

Methods provided for backwards compabibility.

void openReadingPipe (uint8_t number, uint64_t address)
 
void openWritingPipe (uint64_t address)
 
bool isAckPayloadAvailable (void)
 

Protected Member Functions

void beginTransaction ()
 
void endTransaction ()
 

Advanced Operation

Methods you can use to drive the chip in more advanced ways

bool failureDetected
 
void printDetails (void)
 
void printPrettyDetails (void)
 
bool available (uint8_t *pipe_num)
 
bool rxFifoFull ()
 
void powerDown (void)
 
void powerUp (void)
 
bool write (const void *buf, uint8_t len, const bool multicast)
 
bool writeFast (const void *buf, uint8_t len)
 
bool writeFast (const void *buf, uint8_t len, const bool multicast)
 
bool writeBlocking (const void *buf, uint8_t len, uint32_t timeout)
 
bool txStandBy ()
 
bool txStandBy (uint32_t timeout, bool startTx=0)
 
bool writeAckPayload (uint8_t pipe, const void *buf, uint8_t len)
 
void whatHappened (bool &tx_ok, bool &tx_fail, bool &rx_ready)
 
void startFastWrite (const void *buf, uint8_t len, const bool multicast, bool startTx=1)
 
bool startWrite (const void *buf, uint8_t len, const bool multicast)
 
void reUseTX ()
 
uint8_t flush_tx (void)
 
uint8_t flush_rx (void)
 
bool testCarrier (void)
 
bool testRPD (void)
 
bool isValid ()
 
void closeReadingPipe (uint8_t pipe)
 

Optional Configurators

Methods you can use to get or set the configuration of the chip. None are required. Calling begin() sets up a reasonable set of defaults.

uint32_t txDelay
 
uint32_t csDelay
 
void setAddressWidth (uint8_t a_width)
 
void setRetries (uint8_t delay, uint8_t count)
 
void setChannel (uint8_t channel)
 
uint8_t getChannel (void)
 
void setPayloadSize (uint8_t size)
 
uint8_t getPayloadSize (void)
 
uint8_t getDynamicPayloadSize (void)
 
void enableAckPayload (void)
 
void disableAckPayload (void)
 
void enableDynamicPayloads (void)
 
void disableDynamicPayloads (void)
 
void enableDynamicAck ()
 
bool isPVariant (void)
 
void setAutoAck (bool enable)
 
void setAutoAck (uint8_t pipe, bool enable)
 
void setPALevel (uint8_t level, bool lnaEnable=1)
 
uint8_t getPALevel (void)
 
uint8_t getARC (void)
 
bool setDataRate (rf24_datarate_e speed)
 
rf24_datarate_e getDataRate (void)
 
void setCRCLength (rf24_crclength_e length)
 
rf24_crclength_e getCRCLength (void)
 
void disableCRC (void)
 
void maskIRQ (bool tx_ok, bool tx_fail, bool rx_ready)
 
void startConstCarrier (rf24_pa_dbm_e level, uint8_t channel)
 
void stopConstCarrier (void)
 

Detailed Description

Driver class for nRF24L01(+) 2.4GHz Wireless Transceiver.

Examples
examples/AcknowledgementPayloads/AcknowledgementPayloads.ino, examples/GettingStarted/GettingStarted.ino, examples/InterruptConfigure/InterruptConfigure.ino, examples/ManualAcknowledgements/ManualAcknowledgements.ino, examples/MulticeiverDemo/MulticeiverDemo.ino, examples/StreamingData/StreamingData.ino, examples/old_backups/GettingStarted_HandlingFailures/GettingStarted_HandlingFailures.ino, examples/old_backups/TransferTimeouts/TransferTimeouts.ino, examples/old_backups/pingpair_dyn/pingpair_dyn.ino, examples/old_backups/pingpair_irq/pingpair_irq.ino, examples/old_backups/pingpair_sleepy/pingpair_sleepy.ino, examples/old_backups/scanner/scanner.ino, examples/rf24_ATTiny/rf24ping85/rf24ping85.ino, examples_linux/acknowledgementPayloads.cpp, examples_linux/gettingstarted.cpp, examples_linux/manualAcknowledgements.cpp, examples_linux/multiceiverDemo.cpp, and examples_linux/streamingData.cpp.

Definition at line 111 of file RF24.h.

Constructor & Destructor Documentation

◆ RF24()

RF24::RF24 ( uint16_t  _cepin,
uint16_t  _cspin,
uint32_t  _spispeed = RF24_SPI_SPEED 
)

RF24 Constructor

Creates a new instance of this driver. Before using, you create an instance and send in the unique pins that this chip is connected to.

See Related Pages for device specific information

Note
Users can specify default SPI speed by modifying #define RF24_SPI_SPEED in RF24_config.h
For Arduino, SPI speed will only be properly configured this way on devices supporting SPI TRANSACTIONS
Older/Unsupported Arduino devices will use a default clock divider & settings configuration
Linux: The old way of setting SPI speeds using BCM2835 driver enums has been removed
Parameters
_cepinThe pin attached to Chip Enable on the RF module
_cspinThe pin attached to Chip Select
_spispeedThe SPI speed in Hz ie: 1000000 == 1Mhz

Definition at line 423 of file RF24.cpp.

Member Function Documentation

◆ beginTransaction()

void RF24::beginTransaction ( )
inlineprotected

For storing the result of testing the toggleFeatures() affect SPI transactions

Common code for SPI transactions including CSN toggle

Definition at line 86 of file RF24.cpp.

◆ endTransaction()

void RF24::endTransaction ( )
inlineprotected

Definition at line 96 of file RF24.cpp.

◆ begin()

bool RF24::begin ( void  )

Begin operation of the chip

Call this in setup(), before calling any other methods.

radio.begin()

Definition at line 665 of file RF24.cpp.

◆ isChipConnected()

bool RF24::isChipConnected ( )

Checks if the chip is connected to the SPI bus

Definition at line 793 of file RF24.cpp.

◆ startListening()

void RF24::startListening ( void  )

Start listening on the pipes opened for reading.

  1. Be sure to call openReadingPipe() first.
  2. Do not call write() while in this mode, without first calling stopListening().
  3. Call available() to check for incoming traffic, and read() to get it.

Open reading pipe 1 using address 0xCCCECCCECC

byte address[] = {0xCC, 0xCE, 0xCC, 0xCE, 0xCC};
radio.openReadingPipe(1,address);
radio.startListening();
Note
If there was a call to openReadingPipe() about pipe 0 prior to calling this function, then this function will re-write the address that was last set to reading pipe 0. This is because openWritingPipe() will overwrite the address to reading pipe 0 for proper auto-ack functionality.

Definition at line 805 of file RF24.cpp.

◆ stopListening()

void RF24::stopListening ( void  )

Stop listening for incoming messages, and switch to transmit mode.

Do this before calling write().

radio.stopListening();
radio.write(&data, sizeof(data));
Note
When the ACK payloads feature is enabled, the TX FIFO buffers are flushed when calling this function. This is meant to discard any ACK payloads that were not appended to acknowledgment packets.

Definition at line 827 of file RF24.cpp.

◆ available() [1/2]

bool RF24::available ( void  )

Check whether there are bytes available to be read

if(radio.available()){
radio.read(&data,sizeof(data));
}
See also
available(uint8_t*)
Returns
True if there is a payload available, false if none is
Warning
This function relies on the information about the pipe number that received the next available payload. According to the datasheet, the data about the pipe number that received the next available payload is "unreliable" during a FALLING transition on the IRQ pin. This means you should call whatHappened() before calling this function during an ISR (Interrupt Service Routine).
For example:
void isrCallbackFunction() {
bool tx_ds, tx_df, rx_dr;
radio.whatHappened(tx_ds, tx_df, rx_dr); // resets the IRQ pin to HIGH
radio.available(); // returned data should now be reliable
}
void setup() {
pinMode(IRQ_PIN, INPUT);
attachInterrupt(digitalPinToInterrupt(IRQ_PIN), isrCallbackFunction, FALLING);
}
#define INPUT
#define pinMode(pin, direction)

Definition at line 1153 of file RF24.cpp.

◆ read()

void RF24::read ( void *  buf,
uint8_t  len 
)

Read payload data from the RX FIFO buffer(s).

The length of data read is usually the next available payload's length

See also
getPayloadSize()
getDynamicPayloadSize()
Note
I specifically chose void* as a data type to make it easier for beginners to use. No casting needed.
Parameters
bufPointer to a buffer where the data should be written
lenMaximum number of bytes to read into the buffer. This value should match the length of the object referenced using the buf parameter. The absolute maximum number of bytes that can be read in one call is 32 (for dynamic payload lengths) or whatever number was previously passed to setPayloadSize() (for static payload lengths).
Remarks
Remember that each call to read() fetches data from the RX FIFO beginning with the first byte from the first available payload. A payload is not removed from the RX FIFO until it's entire length (or more) is fetched using read().
  • If len parameter's value is less than the available payload's length, then the payload remains in the RX FIFO.
  • If len parameter's value is greater than the first of multiple available payloads, then the data saved to the buf parameter's object will be supplemented with data from the next available payload.
  • If len parameter's value is greater than the last available payload's length, then the last byte in the payload is used as padding for the data saved to the buf parameter's object. The nRF24L01 will repeatedly use the last byte from the last payload even when read() is called with an empty RX FIFO.
Note
To use this function in the python wrapper, remember that only the len parameter is required because this function (in the python wrapper) returns the payload data as a buffer protocol object (bytearray object).
# let `radio` be the instantiated RF24 object
if radio.available():
length = radio.getDynamicPayloadSize() # or radio.getPayloadSize() for static payload sizes
received_payload = radio.read(length)
Returns
No return value. Use available().
Note
This function no longer returns a boolean. Use available to determine if packets are available. The RX_DR Interrupt flag is now cleared with this function instead of when calling available().
if(radio.available()) {
radio.read(&data, sizeof(data));
}

Definition at line 1176 of file RF24.cpp.

◆ write() [1/2]

bool RF24::write ( const void *  buf,
uint8_t  len 
)

Be sure to call openWritingPipe() first to set the destination of where to write to.

This blocks until the message is successfully acknowledged by the receiver or the timeout/retransmit maxima are reached. In the current configuration, the max delay here is 60-70ms.

The maximum size of data written is the fixed payload size, see getPayloadSize(). However, you can write less, and the remainder will just be filled with zeroes.

TX/RX/RT interrupt flags will be cleared every time write is called

Parameters
bufPointer to the data to be sent
lenNumber of bytes to be sent
radio.stopListening();
radio.write(&data,sizeof(data));
Note
The len parameter must be omitted when using the python wrapper because the length of the payload is determined automatically.
To use this function in the python wrapper:
# let `radio` be the instantiated RF24 object
buffer = b"Hello World" # a `bytes` object
radio.write(buffer)
Returns
  • true if the payload was delivered successfully and an acknowledgement (ACK packet) was received. If auto-ack is disabled, then any attempt to transmit will also return true (even if the payload was not received).
  • false if the payload was sent but was not acknowledged with an ACK packet. This condition can only be reported if the auto-ack feature is on.

Definition at line 931 of file RF24.cpp.

◆ openWritingPipe() [1/2]

void RF24::openWritingPipe ( const uint8_t *  address)

New: Open a pipe for writing via byte array. Old addressing format retained for compatibility.

Only one writing pipe can be opened at once, but this function changes the address that is used to transmit (ACK payloads/packets do not apply here). Be sure to call stopListening() prior to calling this function.

Addresses are assigned via a byte array, default is 5 byte address length

uint8_t addresses[][6] = {"1Node", "2Node"};
radio.openWritingPipe(addresses[0]);
uint8_t address[] = { 0xCC, 0xCE, 0xCC, 0xCE, 0xCC };
radio.openWritingPipe(address);
address[0] = 0x33;
radio.openReadingPipe(1, address);
Warning
This function will overwrite the address set to reading pipe 0 as stipulated by the datasheet for proper auto-ack functionality in TX mode. Use this function to ensure proper transmission acknowledgement when the address set to reading pipe 0 (via openReadingPipe()) does not match the address passed to this function. If the auto-ack feature is disabled, then this function will still overwrite the address for reading pipe 0 regardless.
See also
setAddressWidth()
startListening()
Parameters
addressThe address to be used for outgoing transmissions (uses pipe 0). Coordinate this address amongst other receiving nodes (the pipe numbers don't need to match).
Remarks
There is no address length parameter because this function will always write the number of bytes that the radio addresses are configured to use (set with setAddressWidth()).

Definition at line 1213 of file RF24.cpp.

◆ openReadingPipe() [1/2]

void RF24::openReadingPipe ( uint8_t  number,
const uint8_t *  address 
)

Open a pipe for reading

Up to 6 pipes can be open for reading at once. Open all the required reading pipes, and then call startListening().

See also
openWritingPipe()
setAddressWidth()
Note
Pipes 0 and 1 will store a full 5-byte address. Pipes 2-5 will technically only store a single byte, borrowing up to 4 additional bytes from pipe 1 per the assigned address width.
Pipes 1-5 should share the same address, except the first byte. Only the first byte in the array should be unique, e.g.
uint8_t addresses[][6] = {"Prime", "2Node", "3xxxx", "4xxxx"};
openReadingPipe(0, addresses[0]); // address used is "Prime"
openReadingPipe(1, addresses[1]); // address used is "2Node"
openReadingPipe(2, addresses[2]); // address used is "3Node"
openReadingPipe(3, addresses[3]); // address used is "4Node"
void openReadingPipe(uint8_t number, const uint8_t *address)
Definition: RF24.cpp:1265
Warning
If the reading pipe 0 is opened by this function, the address passed to this function (for pipe 0) will be restored at every call to startListening(), but the address for pipe 0 is ONLY restored if the LSB is a non-zero value.
Read http://maniacalbits.blogspot.com/2013/04/rf24-addressing-nrf24l01-radios-require.html to understand how to avoid using malformed addresses. This address restoration is implemented because of the underlying neccessary functionality of openWritingPipe().
Parameters
numberWhich pipe to open. Only pipe numbers 0-5 are available, an address assigned to any pipe number not in that range will be ignored.
addressThe 24, 32 or 40 bit address of the pipe to open.
Remarks
There is no address length parameter because this function will always write the number of bytes (for pipes 0 and 1) that the radio addresses are configured to use (set with setAddressWidth()).

Definition at line 1265 of file RF24.cpp.

◆ printDetails()

void RF24::printDetails ( void  )

Print a giant block of debugging information to stdout

Warning
Does nothing if stdout is not defined. See fdevopen in stdio.h The printf.h file is included with the library for Arduino.
#include <printf.h>
setup(){
Serial.begin(115200);
...
}
void printf_begin(void)
Definition: printf.h:29

Definition at line 528 of file RF24.cpp.

◆ printPrettyDetails()

void RF24::printPrettyDetails ( void  )

Print a giant block of debugging information to stdout. This function differs from printDetails() because it makes the information more understandable without having to look up the datasheet or convert hexadecimal to binary. Only use this function if your application can spare extra bytes of memory.

Warning
Does nothing if stdout is not defined. See fdevopen in stdio.h The printf.h file is included with the library for Arduino.
#include <printf.h>
setup(){
Serial.begin(115200);
...
}
Note
If the automatic acknowledgements feature is configured differently for each pipe, then a binary representation is used in which bits 0-5 represent pipes 0-5 respectively. A 0 means the feature is disabled and a 1 means the feature is enabled.

Definition at line 572 of file RF24.cpp.

◆ available() [2/2]

bool RF24::available ( uint8_t *  pipe_num)

Test whether there are bytes available to be read from the FIFO buffers.

Note
This function is named available_pipe() in the python wrapper. Additionally, the available_pipe() function (which takes no arguments) returns a 2 item tuple containing (ordered by tuple's indices):
  • A boolean describing if there is a payload available to read from the RX FIFO buffers.
  • The pipe number that received the next available payload in the RX FIFO buffers. If the item at the tuple's index 0 is False, then this pipe number is invalid.
To use this function in python:
# let `radio` be the instatiated RF24 object
has_payload, pipe_number = radio.available_pipe() # expand the tuple to 2 variables
if has_payload:
print("Received a payload with pipe", pipe_number)
Parameters
[out]pipe_numWhich pipe has the payload available
uint8_t pipeNum;
if(radio.available(&pipeNum)){
radio.read(&data, sizeof(data));
Serial.print("Received data on pipe ");
Serial.println(pipeNum);
}
Warning
According to the datasheet, the data saved to pipe_num is "unreliable" during a FALLING transition on the IRQ pin. This means you should call whatHappened() before calling this function during an ISR (Interrupt Service Routine).
For example:
void isrCallbackFunction() {
bool tx_ds, tx_df, rx_dr;
radio.whatHappened(tx_ds, tx_df, rx_dr); // resets the IRQ pin to HIGH
uint8_t pipe; // initialize pipe data
radio.available(&pipe); // pipe data should now be reliable
}
void setup() {
pinMode(IRQ_PIN, INPUT);
attachInterrupt(digitalPinToInterrupt(IRQ_PIN), isrCallbackFunction, FALLING);
}
Returns
  • true if there is a payload available in the top (first out) level RX FIFO.
  • false if there is nothing available in the RX FIFO because it is empty.

Definition at line 1160 of file RF24.cpp.

◆ rxFifoFull()

bool RF24::rxFifoFull ( )

Use this function to check if the radio's RX FIFO levels are all occupied. This can be used to prevent data loss because any incoming transmissions are rejected if there is no unoccupied levels in the RX FIFO to store the incoming payload. Remember that each level can hold up to a maximum of 32 bytes.

Returns
  • true if all three 3 levels of the RX FIFO buffers are occupied.
  • false if there is one or more levels available in the RX FIFO buffers. Remember that this does not always mean that the RX FIFO buffers are empty; use available() to see if the RX FIFO buffers are empty or not.

Definition at line 1055 of file RF24.cpp.

◆ powerDown()

void RF24::powerDown ( void  )

Enter low-power mode

To return to normal power mode, call powerUp().

Note
After calling startListening(), a basic radio will consume about 13.5mA at max PA level. During active transmission, the radio will consume about 11.5mA, but this will be reduced to 26uA (.026mA) between sending. In full powerDown mode, the radio will consume approximately 900nA (.0009mA)
radio.powerDown();
avr_enter_sleep_mode(); // Custom function to sleep the device
radio.powerUp();

Definition at line 852 of file RF24.cpp.

◆ powerUp()

void RF24::powerUp ( void  )

Leave low-power mode - required for normal radio operation after calling powerDown()

To return to low power mode, call powerDown().

Note
This will take up to 5ms for maximum compatibility

Definition at line 862 of file RF24.cpp.

◆ write() [2/2]

bool RF24::write ( const void *  buf,
uint8_t  len,
const bool  multicast 
)

Write for single NOACK writes. Optionally disable acknowledgements/auto-retries for a single payload using the multicast parameter set to true.

Can be used with enableAckPayload() to request a response

See also
setAutoAck()
write()
Parameters
bufPointer to the data to be sent
lenNumber of bytes to be sent
multicastRequest ACK response (false), or no ACK response (true). Be sure to have called enableDynamicAck() at least once before setting this parameter.
Returns
  • true if the payload was delivered successfully and an acknowledgement (ACK packet) was received. If auto-ack is disabled, then any attempt to transmit will also return true (even if the payload was not received).
  • false if the payload was sent but was not acknowledged with an ACK packet. This condition can only be reported if the auto-ack feature is on.
Note
The len parameter must be omitted when using the python wrapper because the length of the payload is determined automatically.
To use this function in the python wrapper:
# let `radio` be the instantiated RF24 object
buffer = b"Hello World" # a `bytes` object
radio.write(buffer, False) # False = the multicast parameter

Definition at line 895 of file RF24.cpp.

◆ writeFast() [1/2]

bool RF24::writeFast ( const void *  buf,
uint8_t  len 
)

This will not block until the 3 FIFO buffers are filled with data. Once the FIFOs are full, writeFast will simply wait for success or timeout, and return 1 or 0 respectively. From a user perspective, just keep trying to send the same data. The library will keep auto retrying the current payload using the built in functionality.

Warning
It is important to never keep the nRF24L01 in TX mode and FIFO full for more than 4ms at a time. If the auto retransmit is enabled, the nRF24L01 is never in TX mode long enough to disobey this rule. Allow the FIFO to clear by issuing txStandBy() or ensure appropriate time between transmissions.
Example (Partial blocking):
radio.writeFast(&buf,32); // Writes 1 payload to the buffers
txStandBy(); // Returns 0 if failed. 1 if success. Blocks only until MAX_RT timeout or success. Data flushed on fail.
radio.writeFast(&buf,32); // Writes 1 payload to the buffers
txStandBy(1000); // Using extended timeouts, returns 1 if success. Retries failed payloads for 1 seconds before returning 0.
bool txStandBy()
Definition: RF24.cpp:1062
bool writeFast(const void *buf, uint8_t len)
Definition: RF24.cpp:1015
See also
txStandBy()
write()
writeBlocking()
Parameters
bufPointer to the data to be sent
lenNumber of bytes to be sent
Returns
  • true if the payload was delivered successfully and an acknowledgement (ACK packet) was received. If auto-ack is disabled, then any attempt to transmit will also return true (even if the payload was not received).
  • false if the payload was sent but was not acknowledged with an ACK packet. This condition can only be reported if the auto-ack feature is on.
Note
The len parameter must be omitted when using the python wrapper because the length of the payload is determined automatically.
To use this function in the python wrapper:
# let `radio` be the instantiated RF24 object
buffer = b"Hello World" # a `bytes` object
radio.writeFast(buffer)

Definition at line 1015 of file RF24.cpp.

◆ writeFast() [2/2]

bool RF24::writeFast ( const void *  buf,
uint8_t  len,
const bool  multicast 
)

WriteFast for single NOACK writes. Optionally disable acknowledgements/auto-retries for a single payload using the multicast parameter set to true.

See also
setAutoAck()
Parameters
bufPointer to the data to be sent
lenNumber of bytes to be sent
multicastRequest ACK response (false), or no ACK response (true). Be sure to have called enableDynamicAck() at least once before setting this parameter.
Returns
  • true if the payload passed to buf was loaded in the TX FIFO.
  • false if the payload passed to buf was not loaded in the TX FIFO because a previous payload already in the TX FIFO failed to transmit. This condition can only be reported if the auto-ack feature is on.
Note
The len parameter must be omitted when using the python wrapper because the length of the payload is determined automatically.
To use this function in the python wrapper:
# let `radio` be the instantiated RF24 object
buffer = b"Hello World" # a `bytes` object
radio.writeFast(buffer, False) # False = the multicast parameter

Definition at line 984 of file RF24.cpp.

◆ writeBlocking()

bool RF24::writeBlocking ( const void *  buf,
uint8_t  len,
uint32_t  timeout 
)

This function extends the auto-retry mechanism to any specified duration. It will not block until the 3 FIFO buffers are filled with data. If so the library will auto retry until a new payload is written or the user specified timeout period is reached.

Warning
It is important to never keep the nRF24L01 in TX mode and FIFO full for more than 4ms at a time. If the auto retransmit is enabled, the nRF24L01 is never in TX mode long enough to disobey this rule. Allow the FIFO to clear by issuing txStandBy() or ensure appropriate time between transmissions.

Example (Full blocking):

radio.writeBlocking(&buf, sizeof(buf), 1000); // Wait up to 1 second to write 1 payload to the buffers
radio.txStandBy(1000); // Wait up to 1 second for the payload to send. Return 1 if ok, 0 if failed.
// Blocks only until user timeout or success. Data flushed on fail.
Note
If used from within an interrupt, the interrupt should be disabled until completion, and sei(); called to enable millis().
See also
txStandBy()
write()
writeFast()
Parameters
bufPointer to the data to be sent
lenNumber of bytes to be sent
timeoutUser defined timeout in milliseconds.
Note
The len parameter must be omitted when using the python wrapper because the length of the payload is determined automatically.
To use this function in the python wrapper:
# let `radio` be the instantiated RF24 object
buffer = b"Hello World" # a `bytes` object
radio.writeBlocking(buffer, 1000) # 1000 means wait at most 1 second
Returns
  • true if the payload passed to buf was loaded in the TX FIFO.
  • false if the payload passed to buf was not loaded in the TX FIFO because a previous payload already in the TX FIFO failed to transmit. This condition can only be reported if the auto-ack feature is on.

Definition at line 938 of file RF24.cpp.

◆ txStandBy() [1/2]

bool RF24::txStandBy ( )

This function should be called as soon as transmission is finished to drop the radio back to STANDBY-I mode. If not issued, the radio will remain in STANDBY-II mode which, per the data sheet, is not a recommended operating mode.

Note
When transmitting data in rapid succession, it is still recommended by the manufacturer to drop the radio out of TX or STANDBY-II mode if there is time enough between sends for the FIFOs to empty. This is not required if auto-ack is enabled.

Relies on built-in auto retry functionality.

Example (Partial blocking):

radio.writeFast(&buf,32);
radio.writeFast(&buf,32);
radio.writeFast(&buf,32); //Fills the FIFO buffers up
bool ok = txStandBy(); //Returns 0 if failed. 1 if success.
//Blocks only until MAX_RT timeout or success. Data flushed on fail.
See also
txStandBy(unsigned long timeout)
Returns
  • true if all payloads in the TX FIFO were delivered successfully and an acknowledgement (ACK packet) was received for each. If auto-ack is disabled, then any attempt to transmit will also return true (even if the payload was not received).
  • false if a payload was sent but was not acknowledged with an ACK packet. This condition can only be reported if the auto-ack feature is on.

Definition at line 1062 of file RF24.cpp.

◆ txStandBy() [2/2]

bool RF24::txStandBy ( uint32_t  timeout,
bool  startTx = 0 
)

This function allows extended blocking and auto-retries per a user defined timeout

Fully Blocking Example:

radio.writeFast(&buf,32);
radio.writeFast(&buf,32);
radio.writeFast(&buf,32); //Fills the FIFO buffers up
bool ok = txStandBy(1000); //Returns 0 if failed after 1 second of retries. 1 if success.
//Blocks only until user defined timeout or success. Data flushed on fail.
Note
If used from within an interrupt, the interrupt should be disabled until completion, and sei(); called to enable millis().
Parameters
timeoutNumber of milliseconds to retry failed payloads
startTxIf this is set to true, then this function puts the nRF24L01 in TX Mode. false leaves the primary mode (TX or RX) as it is, which can prevent the mandatory wait time to change modes.
Returns
  • true if all payloads in the TX FIFO were delivered successfully and an acknowledgement (ACK packet) was received for each. If auto-ack is disabled, then any attempt to transmit will also return true (even if the payload was not received).
  • false if a payload was sent but was not acknowledged with an ACK packet. This condition can only be reported if the auto-ack feature is on.

Definition at line 1091 of file RF24.cpp.

◆ writeAckPayload()

bool RF24::writeAckPayload ( uint8_t  pipe,
const void *  buf,
uint8_t  len 
)

Write an acknowledgement (ACK) payload for the specified pipe

The next time a message is received on a specified pipe, the data in buf will be sent back in the ACK payload.

See also
enableAckPayload()
enableDynamicPayloads()
Note
ACK payloads are handled automatically by the radio chip when a regular payload is received. It is important to discard regular payloads in the TX FIFO (using flush_tx()) before loading the first ACK payload into the TX FIFO. This function can be called before and after calling startListening().
Warning
Only three of these can be pending at any time as there are only 3 FIFO buffers.
Dynamic payloads must be enabled.
Note
ACK payloads are dynamic payloads. Calling enableAckPayload() will automatically enable dynamic payloads on pipe 0 (required for TX mode when expecting ACK payloads). To use ACK payloads on any other pipe in RX mode, call enableDynamicPayloads().
Parameters
pipeWhich pipe# (typically 1-5) will get this response.
bufPointer to data that is sent
lenLength of the data to send, up to 32 bytes max. Not affected by the static payload set by setPayloadSize().
Note
The len parameter must be omitted when using the python wrapper because the length of the payload is determined automatically.
To use this function in the python wrapper:
# let `radio` be the instantiated RF24 object
buffer = b"Hello World" # a `bytes` object
radio.writeAckPayload(1, buffer) # load an ACK payload for response on pipe 1
Returns
  • true if the payload was loaded into the TX FIFO.
  • false if the payload wasn't loaded into the TX FIFO because it is already full or the ACK payload feature is not enabled using enableAckPayload().

Definition at line 1393 of file RF24.cpp.

◆ whatHappened()

void RF24::whatHappened ( bool &  tx_ok,
bool &  tx_fail,
bool &  rx_ready 
)

Call this when you get an Interrupt Request (IRQ) to find out why

This function describes what event triggered the IRQ pin to go active LOW and clears the status of all events.

See also
maskIRQ()
Parameters
[out]tx_okThe transmission attempt completed (TX_DS). This does not imply that the transmitted data was received by another radio, rather this only reports if the attempt to send was completed. This will always be true when the auto-ack feature is disabled.
[out]tx_failThe transmission failed to be acknowledged, meaning too many retries (MAX_RT) were made while expecting an ACK packet. This event is only triggered when auto-ack feature is enabled.
[out]rx_readyThere is a newly received payload (RX_DR) saved to RX FIFO buffers. Remember that the RX FIFO can only hold up to 3 payloads. Once the RX FIFO is full, all further received transmissions are rejected until there is space to save new data in the RX FIFO buffers.
Note
This function expects no parameters in the python wrapper. Instead, this function returns a 3 item tuple describing the IRQ events' status.
To use this function in the python wrapper:
# let`radio` be the instantiated RF24 object
tx_ds, tx_df, rx_dr = radio.whatHappened() # get IRQ status flags
print("tx_ds: {}, tx_df: {}, rx_dr: {}".format(tx_ds, tx_df, rx_dr))

Definition at line 1189 of file RF24.cpp.

◆ startFastWrite()

void RF24::startFastWrite ( const void *  buf,
uint8_t  len,
const bool  multicast,
bool  startTx = 1 
)

Non-blocking write to the open writing pipe used for buffered writes

Note
Optimization: This function now leaves the CE pin high, so the radio will remain in TX or STANDBY-II Mode until a txStandBy() command is issued. Can be used as an alternative to startWrite() if writing multiple payloads at once.
Warning
It is important to never keep the nRF24L01 in TX mode with FIFO full for more than 4ms at a time. If the auto retransmit/autoAck is enabled, the nRF24L01 is never in TX mode long enough to disobey this rule. Allow the FIFO to clear by issuing txStandBy() or ensure appropriate time between transmissions.
See also
write()
writeFast()
startWrite()
writeBlocking()

For single noAck writes:

See also
setAutoAck()
Parameters
bufPointer to the data to be sent
lenNumber of bytes to be sent
multicastRequest ACK response (false), or no ACK response (true). Be sure to have called enableDynamicAck() at least once before setting this parameter.
startTxIf this is set to true, then this function sets the nRF24L01's CE pin to active (enabling TX transmissions). false has no effect on the nRF24L01's CE pin and simply loads the payload into the TX FIFO.
Note
The len parameter must be omitted when using the python wrapper because the length of the payload is determined automatically.
To use this function in the python wrapper:
# let `radio` be the instantiated RF24 object
buffer = b"Hello World" # a `bytes` object
radio.startFastWrite(buffer, False, True) # 3rd parameter is optional
# False means expecting ACK response (multicast parameter)
# True means initiate transmission (startTx parameter)

Definition at line 1027 of file RF24.cpp.

◆ startWrite()

bool RF24::startWrite ( const void *  buf,
uint8_t  len,
const bool  multicast 
)

Non-blocking write to the open writing pipe

Just like write(), but it returns immediately. To find out what happened to the send, catch the IRQ and then call whatHappened().

See also
write()
writeFast()
startFastWrite()
whatHappened()

For single noAck writes see:

See also
setAutoAck()
Parameters
bufPointer to the data to be sent
lenNumber of bytes to be sent
multicastRequest ACK response (false), or no ACK response (true). Be sure to have called enableDynamicAck() at least once before setting this parameter.
Returns
  • true if payload was written to the TX FIFO buffers and the transmission was started.
  • false if the TX FIFO is full and the payload could not be written. In this condition, the transmission process is restarted.
Note
The len parameter must be omitted when using the python wrapper because the length of the payload is determined automatically.
To use this function in the python wrapper:
# let `radio` be the instantiated RF24 object
buffer = b"Hello World" # a `bytes` object
radio.startWrite(buffer, False) # False = the multicast parameter

Definition at line 1040 of file RF24.cpp.

◆ reUseTX()

void RF24::reUseTX ( )

The function will instruct the radio to re-use the payload in the top level (first out) of the TX FIFO buffers. This is used internally by writeBlocking() to initiate retries when a TX failure occurs. Retries are automatically initiated except with the standard write(). This way, data is not flushed from the buffer until calling flush_tx(). If the TX FIFO has only the one payload (in the top level), the re-used payload can be overwritten by using write(), writeFast(), writeBlocking(), startWrite(), or startFastWrite(). If the TX FIFO has other payloads enqueued, then the aforementioned functions will attempt to enqueue the a new payload in the TX FIFO (does not overwrite the top level of the TX FIFO). Currently, stopListening() also calls flush_tx() when ACK payloads are enabled (via enableAckPayload()).

Upon exiting, this function will set the CE pin HIGH to initiate the re-transmission process. If only 1 re-transmission is desired, then the CE pin should be set to LOW after the mandatory minumum pulse duration of 10 microseconds.

Remarks
This function only applies when taking advantage of the auto-retry feature. See setAutoAck() and setRetries() to configure the auto-retry feature.
Note
This is to be used AFTER auto-retry fails if wanting to resend using the built-in payload reuse feature. After issuing reUseTX(), it will keep resending the same payload until a transmission failure occurs or the CE pin is set to LOW (whichever comes first). In the event of a re-transmission failure, simply call this function again to resume re-transmission of the same payload.

Definition at line 974 of file RF24.cpp.

◆ flush_tx()

uint8_t RF24::flush_tx ( void  )

Empty all 3 of the TX (transmit) FIFO buffers. This is automatically called by stopListening() if ACK payloads are enabled. However, startListening() does not call this function.

Returns
Current value of status register

Definition at line 347 of file RF24.cpp.

◆ flush_rx()

uint8_t RF24::flush_rx ( void  )

Empty all 3 of the RX (receive) FIFO buffers.

Returns
Current value of status register

Definition at line 339 of file RF24.cpp.

◆ testCarrier()

bool RF24::testCarrier ( void  )

Test whether there was a carrier on the line for the previous listening period.

Useful to check for interference on the current channel.

Returns
true if was carrier, false if not

Definition at line 1453 of file RF24.cpp.

◆ testRPD()

bool RF24::testRPD ( void  )

Test whether a signal (carrier or otherwise) greater than or equal to -64dBm is present on the channel. Valid only on nRF24L01P (+) hardware. On nRF24L01, use testCarrier().

Useful to check for interference on the current channel and channel hopping strategies.

bool goodSignal = radio.testRPD();
if(radio.available()){
Serial.println(goodSignal ? "Strong signal > 64dBm" : "Weak signal < 64dBm" );
radio.read(0,0);
}
Returns
true if a signal less than or equal to -64dBm was detected, false if not.

Definition at line 1460 of file RF24.cpp.

◆ isValid()

bool RF24::isValid ( )
inline

Test whether this is a real radio, or a mock shim for debugging. Setting either pin to 0xff is the way to indicate that this is not a real radio.

Returns
true if this is a legitimate radio

Definition at line 1051 of file RF24.h.

◆ closeReadingPipe()

void RF24::closeReadingPipe ( uint8_t  pipe)

Close a pipe after it has been previously opened. Can be safely called without having previously opened a pipe.

Parameters
pipeWhich pipe number to close, any integer not in range [0, 5] is ignored.

Definition at line 1291 of file RF24.cpp.

◆ setAddressWidth()

void RF24::setAddressWidth ( uint8_t  a_width)

Set the address width from 3 to 5 bytes (24, 32 or 40 bit)

Parameters
a_widthThe address width (in bytes) to use; this can be 3, 4 or 5.

Definition at line 1250 of file RF24.cpp.

◆ setRetries()

void RF24::setRetries ( uint8_t  delay,
uint8_t  count 
)

Set the number of retry attempts and delay between retry attempts when transmitting a payload. The radio is waiting for an acknowledgement (ACK) packet during the delay between retry attempts.

Parameters
delayHow long to wait between each retry, in multiples of 250 us. The minumum of 0 means 250 us, and the maximum of 15 means 4000 us. The default value of 5 means 1500us (5 * 250 + 250).
countHow many retries before giving up. The default/maximum is 15. Use 0 to disable the auto-retry feature all together.
Note
Disable the auto-retry feature on a transmitter still uses the auto-ack feature (if enabled), except it will not retry to transmit if the payload was not acknowledged on the first attempt.

Definition at line 1610 of file RF24.cpp.

◆ setChannel()

void RF24::setChannel ( uint8_t  channel)

Set RF communication channel. The frequency used by a channel is calculated as:

2400 MHz + <channel number> 

Meaning the default channel of 76 uses the approximate frequency of 2476 MHz.

Note
In the python wrapper, this function is the setter of the channel attribute.
To use this function in the python wrapper:
# let `radio` be the instantiated RF24 object
radio.channel = 2 # set the channel to 2 (2402 MHz)
Parameters
channelWhich RF channel to communicate on, 0-125

Definition at line 435 of file RF24.cpp.

◆ getChannel()

uint8_t RF24::getChannel ( void  )

Get RF communication channel

Note
In the python wrapper, this function is the getter of the channel attribute.
To use this function in the python wrapper:
# let `radio` be the instantiated RF24 object
chn = radio.channel # get the channel
Returns
The currently configured RF Channel

Definition at line 441 of file RF24.cpp.

◆ setPayloadSize()

void RF24::setPayloadSize ( uint8_t  size)

Set Static Payload Size

This implementation uses a pre-stablished fixed payload size for all transmissions. If this method is never called, the driver will always transmit the maximum payload size (32 bytes), no matter how much was sent to write().

Note
In the python wrapper, this function is the setter of the payloadSize attribute.
To use this function in the python wrapper:
# let `radio` be the instantiated RF24 object
radio.payloadSize = 16 # set the static payload size to 16 bytes
Parameters
sizeThe number of bytes in the payload

Definition at line 449 of file RF24.cpp.

◆ getPayloadSize()

uint8_t RF24::getPayloadSize ( void  )

Get Static Payload Size

Note
In the python wrapper, this function is the getter of the payloadSize attribute.
To use this function in the python wrapper:
# let `radio` be the instantiated RF24 object
pl_size = radio.payloadSize # get the static payload size
See also
setPayloadSize()
Returns
The number of bytes in the payload

Definition at line 461 of file RF24.cpp.

◆ getDynamicPayloadSize()

uint8_t RF24::getDynamicPayloadSize ( void  )

Get Dynamic Payload Size

For dynamic payloads, this pulls the size of the payload off the chip

Note
Corrupt packets are now detected and flushed per the manufacturer.
if(radio.available()){
if(radio.getDynamicPayloadSize() < 1){
// Corrupt payload has been flushed
return;
}
radio.read(&data,sizeof(data));
}
Returns
Payload length of last-received dynamic payload

Definition at line 1139 of file RF24.cpp.

◆ enableAckPayload()

void RF24::enableAckPayload ( void  )

Enable custom payloads in the acknowledge packets

ACK payloads are a handy way to return data back to senders without manually changing the radio modes on both units.

Remarks
The ACK payload feature requires the auto-ack feature to be enabled for any pipe using ACK payloads. This function does not automatically enable the auto-ack feature on pipe 0 since the auto-ack feature is enabled for all pipes by default.
See also
setAutoAck()
Note
ACK payloads are dynamic payloads. This function automatically enables dynamic payloads on pipe 0 by default. Call enableDynamicPayloads() to enable on all pipes (especially for RX nodes that use pipes other than pipe 0 to receive transmissions expecting responses with ACK payloads).

Definition at line 1348 of file RF24.cpp.

◆ disableAckPayload()

void RF24::disableAckPayload ( void  )

Disable custom payloads on the ackowledge packets

See also
enableAckPayload()

Definition at line 1366 of file RF24.cpp.

◆ enableDynamicPayloads()

void RF24::enableDynamicPayloads ( void  )

Enable dynamically-sized payloads

This way you don't always have to send large packets just to send them once in a while. This enables dynamic payloads on ALL pipes.

Definition at line 1308 of file RF24.cpp.

◆ disableDynamicPayloads()

void RF24::disableDynamicPayloads ( void  )

Disable dynamically-sized payloads

This disables dynamic payloads on ALL pipes. Since Ack Payloads requires Dynamic Payloads, Ack Payloads are also disabled. If dynamic payloads are later re-enabled and ack payloads are desired then enableAckPayload() must be called again as well.

Definition at line 1327 of file RF24.cpp.

◆ enableDynamicAck()

void RF24::enableDynamicAck ( void  )

Enable dynamic ACKs (single write multicast or unicast) for chosen messages.

Note
This function must be called once before using the multicast parameter for any functions that offer it. To use multicast behavior about all outgoing payloads (using pipe 0) or incoming payloads (concerning all RX pipes), use setAutoAck()
See also
setAutoAck() for all pipes
setAutoAck(uint8_t, bool) for individual pipes
radio.write(&data, 32, 1); // Sends a payload with no acknowledgement requested
radio.write(&data, 32, 0); // Sends a payload using auto-retry/autoACK

Definition at line 1380 of file RF24.cpp.

◆ isPVariant()

bool RF24::isPVariant ( void  )

Determine whether the hardware is an nRF24L01+ or not.

Returns
true if the hardware is nRF24L01+ (or compatible) and false if its not.

Definition at line 1413 of file RF24.cpp.

◆ setAutoAck() [1/2]

void RF24::setAutoAck ( bool  enable)

Enable or disable the auto-acknowledgement feature for all pipes. This feature is enabled by default. Auto-acknowledgement responds to every recieved payload with an empty ACK packet. These ACK packets get sent from the receiving radio back to the transmitting radio. To attach an ACK payload to a ACK packet, use writeAckPayload().

If this feature is disabled on a transmitting radio, then the transmitting radio will always report that the payload was recieved (even if it was not). Please remember that this feature's configuration needs to match for transmitting and receiving radios.

Warning
When using the multicast parameter to write(), this feature can be disabled for an individual payload. However, if this feature is disabled, then the multicast parameter will have no effect.
Note
If disabling auto-acknowledgment packets, the ACK payloads feature is also disabled as this feature is required to send ACK payloads.
See also
write()
writeFast()
startFastWrite()
startWrite()
writeAckPayload()
Parameters
enableWhether to enable (true) or disable (false) the auto-acknowledgment feature for all pipes

Definition at line 1420 of file RF24.cpp.

◆ setAutoAck() [2/2]

void RF24::setAutoAck ( uint8_t  pipe,
bool  enable 
)

Enable or disable the auto-acknowledgement feature for a specific pipe. This feature is enabled by default for all pipes. Auto-acknowledgement responds to every recieved payload with an empty ACK packet. These ACK packets get sent from the receiving radio back to the transmitting radio. To attach an ACK payload to a ACK packet, use writeAckPayload().

Pipe 0 is used for TX operations, which include sending ACK packets. If using this feature on both TX & RX nodes, then pipe 0 must have this feature enabled for the RX & TX operations. If this feature is disabled on a transmitting radio's pipe 0, then the transmitting radio will always report that the payload was recieved (even if it was not). Remember to also enable this feature for any pipe that is openly listening to a transmitting radio with this feature enabled.

Warning
If this feature is enabled for pipe 0, then the multicast parameter to write() can be used to disable this feature for an individual payload. However, if this feature is disabled for pipe 0, then the multicast parameter will have no effect.
Note
If disabling auto-acknowledgment packets on pipe 0, the ACK payloads feature is also disabled as this feature is required on pipe 0 to send ACK payloads.
See also
write()
writeFast()
startFastWrite()
startWrite()
writeAckPayload()
enableAckPayloads()
disableAckPayloads()
Parameters
pipeWhich pipe to configure. This number should be in range [0, 5].
enableWhether to enable (true) or disable (false) the auto-acknowledgment feature for the specified pipe

Definition at line 1435 of file RF24.cpp.

◆ setPALevel()

void RF24::setPALevel ( uint8_t  level,
bool  lnaEnable = 1 
)

Set Power Amplifier (PA) level and Low Noise Amplifier (LNA) state

Parameters
levelThe desired Power Amplifier level as defined by rf24_pa_dbm_e.
lnaEnableEnable or Disable the LNA (Low Noise Amplifier) Gain. See table for Si24R1 modules below.
lnaEnable only affects nRF24L01 modules with an LNA chip.
level (enum value) nRF24L01
description
Si24R1
description when
lnaEnable = 1
Si24R1
description when
lnaEnable = 0
RF24_PA_MIN (0) -18 dBm -6 dBm -12 dBm
RF24_PA_LOW (1) -12 dBm -0 dBm -4 dBm
RF24_PA_HIGH (2) -6 dBm 3 dBm 1 dBm
RF24_PA_MAX (3) 0 dBm 7 dBm 4 dBm
Note
The getPALevel() function does not care what was passed lnaEnable parameter.

Definition at line 1467 of file RF24.cpp.

◆ getPALevel()

uint8_t RF24::getPALevel ( void  )

Fetches the current Power Amplifier level.

Returns
One of the values defined by rf24_pa_dbm_e.
See tables in rf24_pa_dbm_e or setPALevel()

Definition at line 1483 of file RF24.cpp.

◆ getARC()

uint8_t RF24::getARC ( void  )

Returns automatic retransmission count (ARC_CNT)

Value resets with each new transmission. Allows roughly estimating signal strength.

Returns
Returns values from 0 to 15.

Definition at line 1491 of file RF24.cpp.

◆ setDataRate()

bool RF24::setDataRate ( rf24_datarate_e  speed)

Set the transmission datarate

Warning
setting RF24_250KBPS will fail for non-plus modules (when isPVariant() returns false).
Parameters
speedSpecify one of the following values (as defined by rf24_datarate_e):
speed (enum value) description
RF24_1MBPS (0) for 1 Mbps
RF24_2MBPS (1) for 2 Mbps
RF24_250KBPS (2) for 250 kbs
Returns
true if the change was successful

Definition at line 1499 of file RF24.cpp.

◆ getDataRate()

rf24_datarate_e RF24::getDataRate ( void  )

Fetches the currently configured transmission datarate

Returns
One of the values defined by rf24_datarate_e.
See table in rf24_datarate_e or setDataRate()

Definition at line 1544 of file RF24.cpp.

◆ setCRCLength()

void RF24::setCRCLength ( rf24_crclength_e  length)

Set the CRC length (in bits)
CRC cannot be disabled if auto-ack is enabled

Parameters
lengthSpecify one of the values (as defined by rf24_crclength_e)
length (enum value) description
RF24_CRC_DISABLED (0) to disable using CRC checksums
RF24_CRC_8 (1) to use 8-bit checksums
RF24_CRC_16 (2) to use 16-bit checksums

Definition at line 1566 of file RF24.cpp.

◆ getCRCLength()

rf24_crclength_e RF24::getCRCLength ( void  )

Get the CRC length (in bits)
CRC checking cannot be disabled if auto-ack is enabled

Returns
One of the values defined by rf24_crclength_e.
See table in rf24_crclength_e or setCRCLength()

Definition at line 1584 of file RF24.cpp.

◆ disableCRC()

void RF24::disableCRC ( void  )

Disable CRC validation

Warning
CRC cannot be disabled if auto-ack/ESB is enabled.

Definition at line 1603 of file RF24.cpp.

◆ maskIRQ()

void RF24::maskIRQ ( bool  tx_ok,
bool  tx_fail,
bool  rx_ready 
)

This function is used to configure what events will trigger the Interrupt Request (IRQ) pin active LOW. The following events can be configured:

  1. "data sent": This does not mean that the data transmitted was recieved, only that the attempt to send it was complete.
  2. "data failed": This means the data being sent was not recieved. This event is only triggered when the auto-ack feature is enabled.
  3. "data received": This means that data from a receiving payload has been loaded into the RX FIFO buffers. Remember that there are only 3 levels available in the RX FIFO buffers.

By default, all events are configured to trigger the IRQ pin active LOW. When the IRQ pin is active, use whatHappened() to determine what events triggered it. Remeber that calling whatHappened() also clears these events' status, and the IRQ pin will then be reset to inactive HIGH.

The following code configures the IRQ pin to only reflect the "data received" event:

radio.maskIRQ(1, 1, 0);
Parameters
tx_oktrue ignores the "data sent" event, false reflects the "data sent" event on the IRQ pin.
tx_failtrue ignores the "data failed" event, false reflects the "data failed" event on the IRQ pin.
rx_readytrue ignores the "data received" event, false reflects the "data received" event on the IRQ pin.

Definition at line 1128 of file RF24.cpp.

◆ startConstCarrier()

void RF24::startConstCarrier ( rf24_pa_dbm_e  level,
uint8_t  channel 
)

Transmission of constant carrier wave with defined frequency and output power

Parameters
levelOutput power to use
channelThe channel to use
Warning
If isPVariant() returns true, then this function takes extra measures that alter some settings. These settings alterations include:

Definition at line 1616 of file RF24.cpp.

◆ stopConstCarrier()

void RF24::stopConstCarrier ( void  )

Stop transmission of constant wave and reset PLL and CONT registers

Warning
this function will powerDown() the radio per recommendation of datasheet.
Note
If isPVariant() returns true, please remember to re-configure the radio's settings
// re-establish default settings
setAutoAck(true);
setRetries(5, 15);
void setRetries(uint8_t delay, uint8_t count)
Definition: RF24.cpp:1610
void setCRCLength(rf24_crclength_e length)
Definition: RF24.cpp:1566
void setAutoAck(bool enable)
Definition: RF24.cpp:1420
@ RF24_CRC_16
Definition: RF24.h:103
See also
startConstCarrier()

Definition at line 1650 of file RF24.cpp.

◆ openReadingPipe() [2/2]

void RF24::openReadingPipe ( uint8_t  number,
uint64_t  address 
)

Open a pipe for reading

Deprecated:
For compatibility with old code only, see newer function openReadingPipe()
Warning
Pipes 1-5 should share the first 32 bits. Only the least significant byte should be unique, e.g.
openReadingPipe(1, 0xF0F0F0F0AA);
openReadingPipe(2, 0xF0F0F0F066);
Pipe 0 is also used by the writing pipe so should typically be avoided as a reading pipe.
If used, the reading pipe 0 address needs to be restored at avery call to startListening(), and the address
is ONLY restored if the LSB is a non-zero value.
See http://maniacalbits.blogspot.com/2013/04/rf24-addressing-nrf24l01-radios-require.html
Parameters
numberWhich pipe# to open, 0-5.
addressThe 40-bit address of the pipe to open.

Definition at line 1225 of file RF24.cpp.

◆ openWritingPipe() [2/2]

void RF24::openWritingPipe ( uint64_t  address)

Open a pipe for writing

Deprecated:
For compatibility with old code only, see newer function openWritingPipe()

Addresses are 40-bit hex values, e.g.:

openWritingPipe(0xF0F0F0F0F0);
void openWritingPipe(const uint8_t *address)
Definition: RF24.cpp:1213
Parameters
addressThe 40-bit address of the pipe to open.

Definition at line 1203 of file RF24.cpp.

◆ isAckPayloadAvailable()

bool RF24::isAckPayloadAvailable ( void  )

Determine if an ack payload was received in the most recent call to write(). The regular available() can also be used.

Deprecated:
Call read() to retrieve the ack payload.
Returns
True if an ack payload is available.

Definition at line 1406 of file RF24.cpp.

Member Data Documentation

◆ failureDetected

bool RF24::failureDetected

If a failure has been detected, it usually indicates a hardware issue. By default the library will cease operation when a failure is detected. This should allow advanced users to detect and resolve intermittent hardware issues.

In most cases, the radio must be re-enabled via radio.begin(); and the appropriate settings applied after a failure occurs, if wanting to re-enable the device immediately.

The three main failure modes of the radio include:

Writing to radio: Radio unresponsive - Fixed internally by adding a timeout to the internal write functions in RF24 (failure handling)

Reading from radio: Available returns true always - Fixed by adding a timeout to available functions by the user. This is implemented internally in RF24Network.

Radio configuration settings are lost - Fixed by monitoring a value that is different from the default, and re-configuring the radio if this setting reverts to the default.

See the included example, GettingStarted_HandlingFailures

if(radio.failureDetected){
radio.begin(); // Attempt to re-configure the radio with defaults
radio.failureDetected = 0; // Reset the detection value
radio.openWritingPipe(addresses[1]); // Re-configure pipe addresses
radio.openReadingPipe(1,addresses[0]);
report_failure(); // Blink leds, send a message, etc. to indicate failure
}

Definition at line 1094 of file RF24.h.

◆ txDelay

uint32_t RF24::txDelay

The driver will delay for this duration when stopListening() is called

When responding to payloads, faster devices like ARM(RPi) are much faster than Arduino:

  1. Arduino sends data to RPi, switches to RX mode
  2. The RPi receives the data, switches to TX mode and sends before the Arduino radio is in RX mode
  3. If AutoACK is disabled, this can be set as low as 0. If AA/ESB enabled, set to 100uS minimum on RPi
Warning
If set to 0, ensure 130uS delay after stopListening() and before any sends

Definition at line 1498 of file RF24.h.

◆ csDelay

uint32_t RF24::csDelay

On all devices but Linux and ATTiny, a small delay is added to the CSN toggling function

This is intended to minimise the speed of SPI polling due to radio commands

If using interrupts or timed requests, this can be set to 0 Default:5

Definition at line 1508 of file RF24.h.


The documentation for this class was generated from the following files: