Driver 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 (uint8_t _cepin, uint8_t _cspin)
	Constructor.
void	begin (void)
	Begin operation of the chip.
void	startListening (void)
	Start listening on the pipes opened for reading.
void	stopListening (void)
	Stop listening for incoming messages.
bool	write (const void *buf, uint8_t len)
	Write to the open writing pipe.
bool	available (void)
	Test whether there are bytes available to be read.
bool	read (void *buf, uint8_t len)
	Read the payload.
void	openWritingPipe (uint64_t address)
	Open a pipe for writing.
void	openReadingPipe (uint8_t number, uint64_t address)
	Open a pipe for reading.
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)
	Set the number and delay of retries upon failed submit.
void	setChannel (uint8_t channel)
	Set RF communication channel.
void	setPayloadSize (uint8_t size)
	Set Static Payload Size.
uint8_t	getPayloadSize (void)
	Get Static Payload Size.
uint8_t	getDynamicPayloadSize (void)
	Get Dynamic Payload Size.
void	enableAckPayload (void)
	Enable custom payloads on the acknowledge packets.
void	enableDynamicPayloads (void)
	Enable dynamically-sized payloads.
bool	isPVariant (void)
	Determine whether the hardware is an nRF24L01+ or not.
void	setAutoAck (bool enable)
	Enable or disable auto-acknowlede packets.
void	setAutoAck (uint8_t pipe, bool enable)
	Enable or disable auto-acknowlede packets on a per pipeline basis.
void	setPALevel (rf24_pa_dbm_e level)
	Set Power Amplifier (PA) level to one of four levels.
rf24_pa_dbm_e	getPALevel (void)
	Fetches the current PA level.
bool	setDataRate (rf24_datarate_e speed)
	Set the transmission data rate.
rf24_datarate_e	getDataRate (void)
	Fetches the transmission data rate.
void	setCRCLength (rf24_crclength_e length)
	Set the CRC length.
rf24_crclength_e	getCRCLength (void)
	Get the CRC length.
void	disableCRC (void)
	Disable CRC validation.
Advanced Operation
Methods you can use to drive the chip in more advanced ways
void	printDetails (void)
	Print a giant block of debugging information to stdout.
void	powerDown (void)
	Enter low-power mode.
void	powerUp (void)
	Leave low-power mode - making radio more responsive.
bool	available (uint8_t *pipe_num)
	Test whether there are bytes available to be read.
void	startWrite (const void *buf, uint8_t len)
	Non-blocking write to the open writing pipe.
void	writeAckPayload (uint8_t pipe, const void *buf, uint8_t len)
	Write an ack payload for the specified pipe.
bool	isAckPayloadAvailable (void)
	Determine if an ack payload was received in the most recent call to write().
void	whatHappened (bool &tx_ok, bool &tx_fail, bool &rx_ready)
	Call this when you get an interrupt to find out why.
bool	testCarrier (void)
	Test whether there was a carrier on the line for the previous listening period.
bool	testRPD (void)
	Test whether a signal (carrier or otherwise) greater than or equal to -64dBm is present on the channel.
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)
	Set chip select pin.
void	ce (int level)
	Set chip enable.
uint8_t	read_register (uint8_t reg, uint8_t *buf, uint8_t len)
	Read a chunk of data in from a register.
uint8_t	read_register (uint8_t reg)
	Read single byte from a register.
uint8_t	write_register (uint8_t reg, const uint8_t *buf, uint8_t len)
	Write a chunk of data to a register.
uint8_t	write_register (uint8_t reg, uint8_t value)
	Write a single byte to a register.
uint8_t	write_payload (const void *buf, uint8_t len)
	Write the transmit payload.
uint8_t	read_payload (void *buf, uint8_t len)
	Read the receive payload.
uint8_t	flush_rx (void)
	Empty the receive buffer.
uint8_t	flush_tx (void)
	Empty the transmit buffer.
uint8_t	get_status (void)
	Retrieve the current status of the chip.
void	print_status (uint8_t status)
	Decode and print the given status to stdout.
void	print_observe_tx (uint8_t value)
	Decode and print the given 'observe_tx' value to stdout.
void	print_byte_register (prog_char *name, uint8_t reg, uint8_t qty=1)
	Print the name and value of an 8-bit register to stdout.
void	print_address_register (prog_char *name, uint8_t reg, uint8_t qty=1)
	Print the name and value of a 40-bit address register to stdout.
void	toggle_features (void)
	Turn on or off the special features of the chip.

Detailed Description

Driver for nRF24L01(+) 2.4GHz Wireless Transceiver.

Examples:: GettingStarted.pde, led_remote.pde, nordic_fob.pde, pingpair.pde, pingpair_irq.pde, pingpair_maple.pde, pingpair_pl.pde, pingpair_sleepy.pde, scanner.pde, and starping.pde.

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.

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	(	prog_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	(	prog_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 ) [protected]

Read single byte from a register.

Parameters:

reg	Which register. Use constants from nRF24L01.h

Returns:: Current value of register reg

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

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().

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

RF24.h

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation