What does this error mean

Projects Programming
1

Hi, I am using the two Sketches from here...
http://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo

The first one, the Tx compiles and loads fine, but the Rx does not.
Scroll down to
YD_nRF24L01_Receive_JoyStick

and this line...
done = radio.read( joystick, sizeof(joystick) );

Is throwing an error. I checked the .h and .cpp files and it all looks good to me, but then... :slight_smile:

Arduino: 1.6.5 (Windows 8.1), Board: "Arduino Nano, ATmega328"
Rx_001.ino: In function 'void loop()':
Rx_001:60: error: void value not ignored as it ought to be
void value not ignored as it ought to be

2

void value not ignored as it ought to be

Usually means that you are trying to get a value from a function that does not return a value.

If only you had posted your complete program.........

3

The sketch on that website is outdated and needs a special library I do not have (to make sense).

radio.available() returns whether something was received in my library, not whether there is a radio.

radio.read() returns a bool in my library, obviously in your library it does not.

4

I was following this video. Maybe he fixed it and assumed I knew enough to do so too. :slight_smile:

The complete program is on the page I mentioned. But here it is

/* YourDuinoStarter Example: nRF24L01 Receive Joystick values

 - WHAT IT DOES: Receives data from another transceiver with
   2 Analog values from a Joystick or 2 Potentiometers
   Displays received values on Serial Monitor
 - SEE the comments after "//" on each line below
 - CONNECTIONS: nRF24L01 Modules See:
 http://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo
   1 - GND
   2 - VCC 3.3V !!! NOT 5V
   3 - CE to Arduino pin 9
   4 - CSN to Arduino pin 10
   5 - SCK to Arduino pin 13
   6 - MOSI to Arduino pin 11
   7 - MISO to Arduino pin 12
   8 - UNUSED
   
 - V1.00 11/26/13
   Based on examples at http://www.bajdi.com/
   Questions: terry@yourduino.com */

/*-----( Import needed libraries )-----*/
#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>
/*-----( Declare Constants and Pin Numbers )-----*/
#define CE_PIN   9
#define CSN_PIN 10

// NOTE: the "LL" at the end of the constant is "LongLong" type
const uint64_t pipe = 0xE8E8F0F0E1LL; // Define the transmit pipe


/*-----( Declare objects )-----*/
RF24 radio(CE_PIN, CSN_PIN); // Create a Radio
/*-----( Declare Variables )-----*/
int joystick[2];  // 2 element array holding Joystick readings

void setup()   /****** SETUP: RUNS ONCE ******/
{
  Serial.begin(9600);
  delay(1000);
  Serial.println("Nrf24L01 Receiver Starting");
  radio.begin();
  radio.openReadingPipe(1,pipe);
  radio.startListening();;
}//--(end setup )---


void loop()   /****** LOOP: RUNS CONSTANTLY ******/
{
  if ( radio.available() )
  {
    // Read the data payload until we've received everything
    bool done = false;
    while (!done)
    {
      // Fetch the data payload
      done = radio.read( joystick, sizeof(joystick) );
      Serial.print("X = ");
      Serial.print(joystick[0]);
      Serial.print(" Y = ");      
      Serial.println(joystick[1]);
    }
  }
  else
  {    
      Serial.println("No radio available");
  }

}//--(end main loop )---

/*-----( Declare User-written Functions )-----*/

//NONE
//*********( THE END )***********

and the .cpp section as this forum said "The message exceeds the maximum allowed length (9000 characters). "

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

  // Fetch the payload
  read_payload( buf, len );

  //Clear the two possible interrupt flags with one command
  write_register(NRF_STATUS,_BV(RX_DR) | _BV(MAX_RT) | _BV(TX_DS) );

}
5

I prefer my version of that routine (which is probably older)

bool RF24::read( void* buf, uint8_t len )
{
  // Fetch the payload
  read_payload( buf, len );

  // was this the last of the data available?
  return read_register(FIFO_STATUS) & _BV(RX_EMPTY);
}