rf24-pio/RF24.h

448 lines
13 KiB
C++

/*
Copyright (C) 2011 James Coliz, Jr. <maniacbug@ymail.com>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
version 2 as published by the Free Software Foundation.
*/
#ifndef __RF24_H__
#define __RF24_H__
#include <inttypes.h>
/**
* Driver for nRF24L01 2.4GHz Wireless Transceiver
*/
class RF24
{
private:
uint8_t ce_pin; /**< "Chip Enable" pin, activates the RX or TX role */
uint8_t csn_pin; /**< SPI Chip select */
uint8_t payload_size; /**< Fixed size of payloads */
boolean ack_payload_available; /**< Whether there is an ack payload waiting */
uint8_t ack_payload_length; /**< Dynamic size of pending ack payload. Note: not used. */
uint64_t pipe0_reading_address; /**< Last address set on pipe 0 for reading. */
protected:
/**
* @name Low-level internal interface.
*
* Protected methods that address the chip directly.
*/
/**@{*/
/**
* Set chip select pin
*
* @param mode HIGH to take this unit off the SPI bus, LOW to put it on
*/
void csn(int mode) ;
/**
* Set chip enable
*
* @param mode 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 ce(int mode);
/**
* Read a chunk of data in from a register
*
* @param reg Which register. Use constants from nRF24L01.h
* @param buf Where to put the data
* @param len How many bytes of data to transfer
* @return Current value of status register
*/
uint8_t read_register(uint8_t reg, uint8_t* buf, uint8_t len) ;
/**
* Read single byte from a register
*
* @param reg Which register. Use constants from nRF24L01.h
* @return Current value of register @p reg
*/
uint8_t read_register(uint8_t reg);
/**
* Write a chunk of data to a register
*
* @param reg Which register. Use constants from nRF24L01.h
* @param buf Where to get the data
* @param len How many bytes of data to transfer
* @return Current value of status register
*/
uint8_t write_register(uint8_t reg, const uint8_t* buf, uint8_t len);
/**
* Write a single byte to a register
*
* @param reg Which register. Use constants from nRF24L01.h
* @param value The new value to write
* @return Current value of status register
*/
uint8_t write_register(uint8_t reg, uint8_t value);
/**
* Write the transmit payload
*
* The size of data written is the fixed payload size, see getPayloadSize()
*
* @param buf Where to get the data
* @param len Number of bytes to be sent
* @return Current value of status register
*/
uint8_t write_payload(const void* buf, uint8_t len);
/**
* Read the receive payload
*
* The size of data read is the fixed payload size, see getPayloadSize()
*
* @param buf Where to put the data
* @param len Maximum number of bytes to read
* @return Current value of status register
*/
uint8_t read_payload(void* buf, uint8_t len) ;
/**
* Read the payload length
*
* For dynamic payloads, this pulls the size of the payload off
* the chip
*
* @return Payload length of last-received dynamic payload
*/
uint8_t read_payload_length(void);
/**
* Empty the receive buffer
*
* @return Current value of status register
*/
uint8_t flush_rx(void);
/**
* Empty the transmit buffer
*
* @return Current value of status register
*/
uint8_t flush_tx(void);
/**
* Retrieve the current status of the chip
*
* @return Current value of status register
*/
uint8_t get_status(void) ;
/**
* Decode and print the given status to stdout
*
* @param status Status value to print
*
* @warning Does nothing if stdout is not defined. See fdevopen in stdio.h
*/
void print_status(uint8_t status) ;
/**
* Decode and print the given 'observe_tx' value to stdout
*
* @param value The observe_tx value to print
*
* @warning Does nothing if stdout is not defined. See fdevopen in stdio.h
*/
void print_observe_tx(uint8_t value) ;
/**
* 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 toggle_features(void);
/**@}*/
public:
/**
* 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.
*
* @param _cepin The pin attached to Chip Enable on the RF module
* @param _cspin The pin attached to Chip Select
*/
RF24(uint8_t _cepin, uint8_t _cspin);
/**
* Begin operation of the chip
*
* Call this in setup(), before calling any other methods.
*/
void begin(void);
/**
* Set RF communication channel
*
* @param channel Which RF channel to communicate on, 0-127
*/
void setChannel(uint8_t channel);
/**
* Set 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
*
* @param size The number of bytes in the payload
*/
void setPayloadSize(uint8_t size);
/**
* Get Payload Size
*
* @see setPayloadSize()
*
* @return The number of bytes in the payload
*/
uint8_t getPayloadSize(void) ;
/**
* Print a giant block of debugging information to stdout
*
* @warning Does nothing if stdout is not defined. See fdevopen in stdio.h
*/
void printDetails(void) ;
/**
* Start listening on the pipes opened for reading.
*
* Be sure to open some pipes for reading first. Do not call 'write'
* while in this mode, without first calling 'stopListening'.
*/
void startListening(void);
/**
* Stop listening for incoming messages
*
* Necessary to do this before writing.
*/
void stopListening(void);
/**
* Enter low-power mode
*
* To return to normal power mode, either write() some data or
* startListening().
*/
void powerDown(void);
/**
* Write to the open writing pipe
*
* 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.
*
* @param buf Pointer to the data to be sent
* @param len Number of bytes to be sent
* @return True if the payload was delivered successfully false if not
*/
boolean write( const void* buf, uint8_t len );
/**
* Test whether there are bytes available to be read
*
* @return True if there is a payload available, false if none is
*/
boolean available(void) ;
/**
* Test whether there are bytes available to be read
*
* @param[out] pipe_num Which pipe has the payload available
* @return True if there is a payload available, false if none is
*/
boolean available(uint8_t* pipe_num);
/**
* 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.
*
* @param buf Pointer to a buffer where the data should be written
* @param len Maximum number of bytes to read into the buffer
* @return True if the payload was delivered successfully false if not
*/
boolean read( void* buf, uint8_t len ) ;
/**
* 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.:
*
* @code
* openWritingPipe(0xF0F0F0F0F0);
* @endcode
*
* @param 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 openWritingPipe(uint64_t address);
/**
* Open a pipe for reading
*
* Up to 5 pipes can be open for reading at once. Open all the
* reading pipes, and then call startListening().
*
* @see openWritingPipe
*
* @warning Pipes 1-5 should share the first 32 bits.
* Only the least significant byte should be unique, e.g.
*
* @code
* openReadingPipe(1,0xF0F0F0F0AA);
* openReadingPipe(2,0xF0F0F0F066);
* @endcode
*
* @todo Enforce the restriction that pipes 1-5 must share the top 32 bits
*
* @param number Which pipe# to open, 0-5.
* @param address The 40-bit address of the pipe to open.
*/
void openReadingPipe(uint8_t number, uint64_t address);
/**
* 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 the
* pingpair_pl.pde example.
*/
void enableAckPayload(void);
/**
* Write an ack payload for the specified pipe
*
* The next time a message is received on @p pipe, the data in @p 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.
*
* @param pipe Which pipe# (typically 1-5) will get this response.
* @param buf Pointer to data that is sent
* @param len Length of the data to send, up to 32 bytes max. Not affected
* by the static payload set by setPayloadSize().
*/
void writeAckPayload(uint8_t pipe, const void* buf, uint8_t len);
/**
* 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.
*
* @return True if an ack payload is available.
*/
boolean isAckPayloadAvailable(void);
};
/**
* @example pingpair.pde
*
* This is an example of how to use the RF24 class. Write this sketch to two
* different nodes, connect the role_pin to ground on one. The ping node sends
* the current time to the pong node, which responds by sending the value back.
* The ping node can then see how long the whole cycle took.
*/
/**
* @example starping.pde
*
* This sketch is a more complex example of using the RF24 library for Arduino.
* Deploy this on up to six nodes. Set one as the 'pong receiver' by tying the
* role_pin low, and the others will be 'ping transmit' units. The ping units
* unit will send out the value of millis() once a second. The pong unit will
* respond back with a copy of the value. Each ping unit can get that response
* back, and determine how long the whole cycle took.
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.
*
* This example requires a bit more complexity to determine which unit is which.
* The pong receiver is identified by having its role_pin tied to ground.
* The ping senders are further differentiated by a byte in eeprom.
*/
/**
* @example pingpair_pl.pde
*
* This is an example of how to do two-way communication without changing
* transmit/receive modes. Here, a payload is set to the transmitter within
* the Ack packet of each transmission. Note that the payload is set BEFORE
* the sender's message arrives.
*/
/**
* @example pingpair_sleepy.pde
*
* This is an example of how to use the RF24 class to create a battery-
* efficient system. It is just like the pingpair.pde example, but the
* ping node powers down the radio and sleeps the MCU after every
* ping/pong cycle.
*/
/**
* @mainpage Driver for nRF24L01 2.4GHz Wireless Transceiver
*
* Design Goals: This library is designed to be...
* @li Maximally compliant with the intended operation of the chip
* @li Easy for beginners to use
* @li Consumed with a public interface that's similiar to other Arduino standard libraries
* @li Built against the standard SPI library.
*
* Please refer to:
*
* @li <a href="http://maniacbug.github.com/RF24/">Documentation Main Page</a>
* @li <a href="http://maniacbug.github.com/RF24/classRF24.html">RF24 Class Documentation</a>
* @li <a href="https://github.com/maniacbug/RF24/">Source Code</a>
* @li <a href="https://github.com/maniacbug/RF24/archives/master">Downloads Page</a>
* @li <a href="http://www.nordicsemi.com/files/Product/data_sheet/nRF24L01_Product_Specification_v2_0.pdf">Chip Datasheet</a>
*
* This chip uses the SPI bus, plus two chip control pins. Remember that pin 10 must still remain an output, or
* the SPI hardware will go into 'slave' mode.
*/
#endif // __RF24_H__
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