dtostrf in Energia

[maksms82 0]

Is supported in Energia dtostrf?

[Bernard 7]

Hi,

 

same problem here ... dtostrf is ok on arduino

 

as a newbee I would be happy to get information

 

Thank  you

[spirilis 1,265]

Huh, doing a quick google search, apparently dtostrf is a unique function that only comes with the AVR libc. Energia probably doesn't support it but it doesn't sound hard to emulate.

[energia 485]

I have not looked at it in detail but it seems that sprintf() for floats is broken in Arduino/AVR. It seems that dtostrf() was implemented to offered as an alternative.

The details are here: http://dereenigne.org/arduino/arduino-float-to-string

 

On Stellaris sprintf() for floats is fully functional and you should use this to convert floats to strings.

// Allocate enough to store PI with with 4 decimals.
char str[5];

void setup()
{
  Serial.begin(115200);

  Serial.print("PI in a string: ");
  // Print PI to a string with 4 decimals
  sprintf(str, "%.4f", PI);
  // Print the string to the serial terminal
  Serial.println(str);
}

void loop()
{
 // Nothing to do here
}

[Bernard 7]

Hi,

 

Thank you very much spirilis and Energia

 

Salutations

[Bernard 7]

hi,

 

Thank you for code.. it works ok  but when i use it  in this code :

/* Stellaris LM4F */


#include <Enrf24.h>
#include <nRF24L01.h>
#include <string.h>
#include <SPI.h>

Enrf24 radio(PA_5,PA_6,PA_7);  // CE, CSN, IRQ + SCK/MOSI/MISO ==> PB_4/PB_7/PB_6

char str[5];


char txaddr[] = {'d','e','v','-','0'}; 
//int intvar;
const char *str_on = "OK";


//void dump_radio_status_to_serialport(uint8_t);

void setup() {
  Serial.begin(9600);

  SPI.setModule(2); // SPI 2
  SPI.begin();
  SPI.setDataMode(SPI_MODE0);
  SPI.setBitOrder(1);

  radio.begin();  // Defaults 1Mbps, channel 0, max TX power
  //dump_radio_status_to_serialport(radio.radioState());

  radio.setTXaddress((void*)txaddr);
}

void loop()
{  
  sprintf(str, "%.4f", PI);
  radio.print(str);
  radio.flush();  // Force transmit (don't wait for any more data)
  delay(500);
  
}

Nothing on the receiver side.

 

Google didn't help me .....

 

Thank you

 

Salutations

 

-Bernard

[spirilis 1,265]

Have you established that data is getting over to the receiver side? E.g. radio.print("Hi!")

[Bernard 7]

Hi,

 

I am sorry and apologize for that, I was not clear enough .

 

Sending a string is ok .

 

Thank you

 

-Bernard

[Bernard 7]

Hi again,

 

I have found another way to convert float to string :

void setup()
{
  Serial.begin(9600);
}

char buffer[12];  
                  
void loop()
{
  float value = 150.51;
  itoa(int(value), buffer, 10);
  int dec = (value - (int)value) * 100;
  itoa(abs(dec), buffer, 10);
  Serial.println( value);  
  delay(1000);
}

It compiles on msp430G2553, F5529  but itoa is unknown when compiling on LM4F120 and Tiva C

 

Salutations

[energia 485]

itoa is not a standard function. e.g it is not included in stdlib.h. The libc for msp430 shipped with Energia implements a custom function for itoa. The libc included in the TivaC/Stellaris arm toolchain does not.

 

I would stick with the sprintf version since you already have that working. If Serial.print() prints the right value then I would check the Enrf24 code.

Where did the Enrf24 library come from?

 

Edit: More details here: http://stackoverflow.com/questions/10162733/atoi-is-a-standard-function-but-itoa-is-not-why

[spirilis 1,265]

Enrf24 is a library I wrote to support the Nordic nRF24L01+ in Energia (there are other Arduino libs out there that do this, but I wanted to take a stab at it "my way" after becoming very familiar with the hardware.)

[Bernard 7]

Hi,

 

@@energia : Thank you for information. I have tried to use sprintf but,  when using it,  program crashes and I don't know why .

 

I have found on the web   itoa  code that works .

 

@@spirilis : thank you very much for this nice library , it helps me a lot in my wireless domotic project.

 

Salutations.

[energia 485]

Thanks for updating the post!

What was crashing it? sprintf or something else? sprintf should not cause any issues. If it does then it is a bug and needs to be looked at.

[Bernard 7]

Hi,

 

I am sorry, sprintf is ok now, I did not allocate enough for buffer .

 

Thank you and salutations.

[Bernard 7]

Hello,

 

I finally got sprintf working. I am able to send and receive datas from BMP085

 

 

here is my working code:

/* Stellaris LM4F120
   nRF24L01 TX
   BMP085   
   SPI module 2
   I2C module 0
   21/01/2014
*/
#include<Wire.h>
#include "BMP085_t.h"  // in a IDE tab .. template from chicken
#include <Enrf24.h>
#include <nRF24L01.h>
#include <string.h>
#include <SPI.h>

Enrf24 radio(PA_5,PA_6,PA_7);  // CE, CSN, IRQ + SCK/MOSI/MISO ==> PB_4/PB_7/PB_6

char txaddr[] = {'d','e','v','-','0','\0'}; 

BMP085<0> PSensor;  

void setup() {
  Serial.begin(9600);
  Wire.setModule(0);
  Wire.begin(); // initialize I2C that connects to sensor
  PSensor.begin(); // initalize pressure sensor
  SPI.setModule(2); // SPI 2
  SPI.begin();
  SPI.setDataMode(SPI_MODE0);
  SPI.setBitOrder(1);

  radio.begin();  // Defaults 1Mbps, channel 0, max TX power
  radio.setTXaddress((void*)txaddr);
}

//************************************************************************

void loop()
{ 
  char str[5];
  long value;
  PSensor.refresh(); // read  sensor data BMP085
  PSensor.calculate();   
   
  value = ((PSensor.pressure+50)/100);
  sprintf(str, "%.2d", value); 
  radio.print(str);
  
  radio.print("---");
  
  value = (PSensor.temperature/10);
  sprintf(str, "%.2d", value);
   radio.print(str);
  
  
  radio.flush();  // Force transmit (don't wait for any more data)
  delay(1000);
  
}
//*************************************************************************

LM4F120 on the receiver side.

 

Thank you all who helped me.

 

Salutations