#include <RF24.h>

Public Member Functions
Primary public interface
These are the main methods you need to operate the chip
	RF24 (uint8_t _cepin, uint8_t _cspin)

void	begin (void)

void	startListening (void)

void	stopListening (void)

bool	write (const void *buf, uint8_t len)

bool	available (void)

bool	read (void *buf, uint8_t len)

void	openWritingPipe (uint64_t address)

void	openReadingPipe (uint8_t number, uint64_t address)

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.
void	setRetries (uint8_t delay, uint8_t count)

void	setChannel (uint8_t channel)

void	setPayloadSize (uint8_t size)

uint8_t	getPayloadSize (void)

uint8_t	getDynamicPayloadSize (void)

void	enableAckPayload (void)

void	enableDynamicPayloads (void)

bool	isPVariant (void)

void	setAutoAck (bool enable)

void	setAutoAck (uint8_t pipe, bool enable)

void	setPALevel (rf24_pa_dbm_e level)

rf24_pa_dbm_e	getPALevel (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)

Advanced Operation
Methods you can use to drive the chip in more advanced ways
void	printDetails (void)

void	powerDown (void)

void	powerUp (void)

bool	available (uint8_t *pipe_num)

void	startWrite (const void *buf, uint8_t len)

void	writeAckPayload (uint8_t pipe, const void *buf, uint8_t len)

bool	isAckPayloadAvailable (void)

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

bool	testCarrier (void)

bool	testRPD (void)

bool	isValid ()

Protected Member Functions
Low-level internal interface.
Protected methods that address the chip directly. Regular users cannot ever call these. They are documented for completeness and for developers who may want to extend this class.
void	csn (int mode)

void	ce (int level)

uint8_t	read_register (uint8_t reg, uint8_t *buf, uint8_t len)

uint8_t	read_register (uint8_t reg)

uint8_t	write_register (uint8_t reg, const uint8_t *buf, uint8_t len)

uint8_t	write_register (uint8_t reg, uint8_t value)

uint8_t	write_payload (const void *buf, uint8_t len)

uint8_t	read_payload (void *buf, uint8_t len)

uint8_t	flush_rx (void)

uint8_t	flush_tx (void)

uint8_t	get_status (void)

void	print_status (uint8_t status)

void	print_observe_tx (uint8_t value)

void	print_byte_register (const char *name, uint8_t reg, uint8_t qty=1)

void	print_address_register (const char *name, uint8_t reg, uint8_t qty=1)

void	toggle_features (void)

Detailed Description

Driver for nRF24L01(+) 2.4GHz Wireless Transceiver

Constructor & Destructor Documentation

RF24::RF24	(	uint8_t	_cepin,
		uint8_t	_cspin
	)

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.

Parameters

_cepin	The pin attached to Chip Enable on the RF module
_cspin	The pin attached to Chip Select

Member Function Documentation

bool RF24::available ( void )

Test whether there are bytes available to be read

Returns: True if there is a payload available, false if none is

bool RF24::available ( uint8_t * pipe_num )

Test whether there are bytes available to be read

Use this version to discover on which pipe the message arrived.

Parameters

[out] pipe_num Which pipe has the payload available

Returns: True if there is a payload available, false if none is

void RF24::begin ( void )

Begin operation of the chip

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

void RF24::ce ( int level )

protected

Set chip enable

Parameters

level HIGH to actively begin transmission or LOW to put in standby. Please see data sheet for a much more detailed description of this pin.

void RF24::csn ( int mode )

protected

Set chip select pin

Running SPI bus at PI_CLOCK_DIV2 so we don't waste time transferring data and best of all, we make use of the radio's FIFO buffers. A lower speed means we're less likely to effectively leverage our FIFOs and pay a higher AVR runtime cost as toll.

Parameters

mode	HIGH to take this unit off the SPI bus, LOW to put it on

void RF24::disableCRC ( void )

Disable CRC validation

void RF24::enableAckPayload ( void )

Enable custom payloads on the acknowledge packets

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

See also: examples/pingpair_pl/pingpair_pl.pde

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.

See also: examples/pingpair_pl/pingpair_dyn.pde

uint8_t RF24::flush_rx ( void )

protected

Empty the receive buffer

Returns: Current value of status register

uint8_t RF24::flush_tx ( void )

protected

Empty the transmit buffer

Returns: Current value of status register

uint8_t RF24::get_status ( void )

protected

Retrieve the current status of the chip

Returns: Current value of status register

rf24_crclength_e RF24::getCRCLength ( void )

Get the CRC length

Returns: RF24_DISABLED if disabled or RF24_CRC_8 for 8-bit or RF24_CRC_16 for 16-bit

rf24_datarate_e RF24::getDataRate ( void )

Fetches the transmission data rate

Returns: Returns the hardware's currently configured datarate. The value is one of 250kbs, RF24_1MBPS for 1Mbps, or RF24_2MBPS, as defined in the rf24_datarate_e enum.

uint8_t RF24::getDynamicPayloadSize ( void )

Get Dynamic Payload Size

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

Returns: Payload length of last-received dynamic payload

rf24_pa_dbm_e RF24::getPALevel ( void )

Fetches the current PA level.

Returns: Returns a value from the rf24_pa_dbm_e enum describing the current PA setting. Please remember, all values represented by the enum mnemonics are negative dBm. See setPALevel for return value descriptions.

uint8_t RF24::getPayloadSize ( void )

Get Static Payload Size

See also: setPayloadSize()

Returns: The number of bytes in the payload

bool RF24::isAckPayloadAvailable ( void )

Determine if an ack payload was received in the most recent call to write().

Call read() to retrieve the ack payload.

Warning: Calling this function clears the internal flag which indicates a payload is available. If it returns true, you must read the packet out as the very next interaction with the radio, or the results are undefined.

Returns: True if an ack payload is available.

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.

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

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

Open a pipe for reading

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

See also: openWritingPipe

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 if you open pipe 0 for reading, and then startListening(), it will overwrite the writing pipe. Ergo, do an openWritingPipe() again before write().

Todo:: Enforce the restriction that pipes 1-5 must share the top 32 bits

Parameters

number	Which pipe# to open, 0-5.
address	The 40-bit address of the pipe to open.

void RF24::openWritingPipe ( uint64_t address )

Open a pipe for writing

Only one pipe can be open at once, but you can change the pipe you'll listen to. Do not call this while actively listening. Remember to stopListening() first.

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

openWritingPipe(0xF0F0F0F0F0);

Parameters

address The 40-bit address of the pipe to open. This can be any value whatsoever, as long as you are the only one writing to it and only one other radio is listening to it. Coordinate these pipe addresses amongst nodes on the network.

void RF24::powerDown ( void )

Enter low-power mode

To return to normal power mode, either write() some data or startListening, or powerUp().

void RF24::powerUp ( void )

Leave low-power mode - making radio more responsive

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

void RF24::print_address_register	(	const char *	name,
		uint8_t	reg,
		uint8_t	qty = `1`
	)

protected

Print the name and value of a 40-bit address register to stdout

Optionally it can print some quantity of successive registers on the same line. This is useful for printing a group of related registers on one line.

Parameters

name	Name of the register
reg	Which register. Use constants from nRF24L01.h
qty	How many successive registers to print

void RF24::print_byte_register	(	const char *	name,
		uint8_t	reg,
		uint8_t	qty = `1`
	)

protected

Print the name and value of an 8-bit register to stdout

Optionally it can print some quantity of successive registers on the same line. This is useful for printing a group of related registers on one line.

Parameters

name	Name of the register
reg	Which register. Use constants from nRF24L01.h
qty	How many successive registers to print

void RF24::print_observe_tx ( uint8_t value )

protected

Decode and print the given 'observe_tx' value to stdout

Parameters

value The observe_tx value to print

Warning: Does nothing if stdout is not defined. See fdevopen in stdio.h

void RF24::print_status ( uint8_t status )

protected

Decode and print the given status to stdout

Parameters

status Status value to print

Warning: Does nothing if stdout is not defined. See fdevopen in stdio.h

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

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

Read the payload

Return the last payload received

The size of data read is the fixed payload size, see getPayloadSize()

Note: I specifically chose 'void*' as a data type to make it easier for beginners to use. No casting needed.

Parameters

buf	Pointer to a buffer where the data should be written
len	Maximum number of bytes to read into the buffer

Returns: True if the payload was delivered successfully false if not

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

protected

Read the receive payload

The size of data read is the fixed payload size, see getPayloadSize()

Parameters

buf	Where to put the data
len	Maximum number of bytes to read

Returns: Current value of status register

uint8_t RF24::read_register	(	uint8_t	reg,
		uint8_t *	buf,
		uint8_t	len
	)

protected

Read a chunk of data in from a register

Parameters

reg	Which register. Use constants from nRF24L01.h
buf	Where to put the data
len	How many bytes of data to transfer

Returns: Current value of status register

uint8_t RF24::read_register ( uint8_t reg )

protected

Read single byte from a register

Parameters

reg	Which register. Use constants from nRF24L01.h

Returns: Current value of register reg

void RF24::setAutoAck ( bool enable )

Enable or disable auto-acknowlede packets

This is enabled by default, so it's only needed if you want to turn it off for some reason.

Parameters

enable Whether to enable (true) or disable (false) auto-acks

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

Enable or disable auto-acknowlede packets on a per pipeline basis.

AA is enabled by default, so it's only needed if you want to turn it off/on for some reason on a per pipeline basis.

Parameters

pipe	Which pipeline to modify
enable	Whether to enable (true) or disable (false) auto-acks

void RF24::setChannel ( uint8_t channel )

Set RF communication channel

Parameters

channel Which RF channel to communicate on, 0-127

void RF24::setCRCLength ( rf24_crclength_e length )

Set the CRC length

Parameters

length RF24_CRC_8 for 8-bit or RF24_CRC_16 for 16-bit

bool RF24::setDataRate ( rf24_datarate_e speed )

Set the transmission data rate

Warning: setting RF24_250KBPS will fail for non-plus units

Parameters

speed RF24_250KBPS for 250kbs, RF24_1MBPS for 1Mbps, or RF24_2MBPS for 2Mbps

Returns: true if the change was successful

void RF24::setPALevel ( rf24_pa_dbm_e level )

Set Power Amplifier (PA) level to one of four levels. Relative mnemonics have been used to allow for future PA level changes. According to 6.5 of the nRF24L01+ specification sheet, they translate to: RF24_PA_MIN=-18dBm, RF24_PA_LOW=-12dBm, RF24_PA_MED=-6dBM, and RF24_PA_HIGH=0dBm.

Parameters

level Desired PA level.

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().

Todo:: Implement variable-sized payloads feature

Parameters

size	The number of bytes in the payload

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

Set the number and delay of retries upon failed submit

Parameters

delay	How long to wait between each retry, in multiples of 250us, max is 15. 0 means 250us, 15 means 4000us.
count	How many retries before giving up, max 15

void RF24::startListening ( void )

Start listening on the pipes opened for reading.

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

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

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(); whatHappened()

Parameters

buf	Pointer to the data to be sent
len	Number of bytes to be sent

Returns: True if the payload was delivered successfully false if not

void RF24::stopListening ( void )

Stop listening for incoming messages

Do this before calling write().

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

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.

Returns: true if signal => -64dBm, false if not

void RF24::toggle_features ( void )

protected

Turn on or off the special features of the chip

The chip has certain 'features' which are only available when the 'features' are enabled. See the datasheet for details.

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

Call this when you get an interrupt to find out why

Tells you what caused the interrupt, and clears the state of interrupts.

Parameters

[out]	tx_ok	The send was successful (TX_DS)
[out]	tx_fail	The send failed, too many retries (MAX_RT)
[out]	rx_ready	There is a message waiting to be read (RX_DS)

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

Write to the open writing pipe

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 60ms.

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.

Parameters

buf	Pointer to the data to be sent
len	Number of bytes to be sent

Returns: True if the payload was delivered successfully false if not

uint8_t RF24::write_payload	(	const void *	buf,
		uint8_t	len
	)

protected

Write the transmit payload

The size of data written is the fixed payload size, see getPayloadSize()

Parameters

buf	Where to get the data
len	Number of bytes to be sent

Returns: Current value of status register

uint8_t RF24::write_register	(	uint8_t	reg,
		const uint8_t *	buf,
		uint8_t	len
	)

protected

Write a chunk of data to a register

Parameters

reg	Which register. Use constants from nRF24L01.h
buf	Where to get the data
len	How many bytes of data to transfer

Returns: Current value of status register

uint8_t RF24::write_register	(	uint8_t	reg,
		uint8_t	value
	)

protected

Write a single byte to a register

Parameters

reg	Which register. Use constants from nRF24L01.h
value	The new value to write

Returns: Current value of status register

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

Write an ack payload for the specified pipe

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

Warning: According to the data sheet, only three of these can be pending at any time. I have not tested this.

Parameters

pipe	Which pipe# (typically 1-5) will get this response.
buf	Pointer to data that is sent
len	Length of the data to send, up to 32 bytes max. Not affected by the static payload set by setPayloadSize().

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation