Optimized High Speed NRF24L01+ Driver Class Documenation  V1.0
TMRh20 2014 - Optimized Fork of NRF24L01+ Driver
rf24ping85.ino

New: Contributed by https://github.com/tong67
This is an example of how to use the RF24 class to communicate with ATtiny85 and other node.

/*
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.
rf24ping85.ino by tong67 ( https://github.com/tong67 )
This is an example of how to use the RF24 class to communicate with ATtiny85 and other node.
Write this sketch to an ATtiny85. It will act like the 'transmit' mode of GettingStarted.ino
Write GettingStarted.ino sketch to UNO (or other board or RPi) and put the node in 'receiver' mode.
The ATtiny85 will transmit a counting number every second starting from 1.
The ATtiny85 uses the tiny-core by CodingBadly (https://code.google.com/p/arduino-tiny/)
When direct use of 3v3 does not work (UNO boards have bad 3v3 line) use 5v with LED (1.8V ~ 2.2V drop)
For low power consumption solutions floating pins (SCK and MOSI) should be pulled high or low with eg. 10K
** Hardware configuration **
ATtiny25/45/85 Pin map with CE_PIN 3 and CSN_PIN 4
+-\/-+
NC PB5 1|o |8 Vcc --- nRF24L01 VCC, pin2 --- LED --- 5V
nRF24L01 CE, pin3 --- PB3 2| |7 PB2 --- nRF24L01 SCK, pin5
nRF24L01 CSN, pin4 --- PB4 3| |6 PB1 --- nRF24L01 MOSI, pin7
nRF24L01 GND, pin1 --- GND 4| |5 PB0 --- nRF24L01 MISO, pin6
+----+
ATtiny25/45/85 Pin map with CE_PIN 3 and CSN_PIN 3 => PB3 and PB4 are free to use for application
Circuit idea from http://nerdralph.blogspot.ca/2014/01/nrf24l01-control-with-3-attiny85-pins.html
Original RC combination was 1K/100nF. 22K/10nF combination worked better.
For best settletime delay value in RF24::csn() the timingSearch3pin.ino scatch can be used.
This configuration is enabled when CE_PIN and CSN_PIN are equal, e.g. both 3
Because CE is always high the power consumption is higher than for 5 pins solution
^^
+-\/-+ nRF24L01 CE, pin3 ------| //
PB5 1|o |8 Vcc --- nRF24L01 VCC, pin2 ------x----------x--|<|-- 5V
NC PB3 2| |7 PB2 --- nRF24L01 SCK, pin5 --|<|---x-[22k]--| LED
NC PB4 3| |6 PB1 --- nRF24L01 MOSI, pin6 1n4148 |
nRF24L01 GND, pin1 -x- GND 4| |5 PB0 --- nRF24L01 MISO, pin7 |
| +----+ |
|-----------------------------------------------||----x-- nRF24L01 CSN, pin4
10nF
ATtiny24/44/84 Pin map with CE_PIN 8 and CSN_PIN 7
Schematic provided and successfully tested by Carmine Pastore (https://github.com/Carminepz)
+-\/-+
nRF24L01 VCC, pin2 --- VCC 1|o |14 GND --- nRF24L01 GND, pin1
PB0 2| |13 AREF
PB1 3| |12 PA1
PB3 4| |11 PA2 --- nRF24L01 CE, pin3
PB2 5| |10 PA3 --- nRF24L01 CSN, pin4
PA7 6| |9 PA4 --- nRF24L01 SCK, pin5
nRF24L01 MOSI, pin7 --- PA6 7| |8 PA5 --- nRF24L01 MISO, pin6
+----+
*/
// CE and CSN are configurable, specified values for ATtiny85 as connected above
#define CE_PIN 3
#define CSN_PIN 4
//#define CSN_PIN 3 // uncomment for ATtiny85 3 pins solution
#include "RF24.h"
RF24 radio(CE_PIN, CSN_PIN);
byte addresses[][6] = {
"1Node","2Node"};
unsigned long payload = 0;
void setup() {
// Setup and configure rf radio
radio.begin(); // Start up the radio
radio.setAutoAck(1); // Ensure autoACK is enabled
radio.setRetries(15,15); // Max delay between retries & number of retries
radio.openWritingPipe(addresses[1]); // Write to device address '2Node'
radio.openReadingPipe(1,addresses[0]); // Read on pipe 1 for device address '1Node'
radio.startListening(); // Start listening
}
void loop(void){
radio.stopListening(); // First, stop listening so we can talk.
payload++;
radio.write( &payload, sizeof(unsigned long) );
radio.startListening(); // Now, continue listening
unsigned long started_waiting_at = micros(); // Set up a timeout period, get the current microseconds
boolean timeout = false; // Set up a variable to indicate if a response was received or not
while ( !radio.available() ){ // While nothing is received
if (micros() - started_waiting_at > 200000 ){ // If waited longer than 200ms, indicate timeout and exit while loop
timeout = true;
break;
}
}
if ( !timeout ){ // Describe the results
unsigned long got_time; // Grab the response, compare, and send to debugging spew
radio.read( &got_time, sizeof(unsigned long) );
}
// Try again 1s later
delay(1000);
}