Where does MySensor store in EEPROM

[mfalkvidd]

@AWI could you clarify where 256 is mentioned?

Edit: Found it, on https://www.mysensors.org/download/sensor_api_20#saving-state

Yes, you are correct. "You have 256 bytes to play with" can not be true for an AtMega328. I've started a discussion for that page, https://forum.mysensors.org/topic/4832/mysensors-library-v2-0-x/

[A Former User]

Hi I'm making a pH sensor with Sparkeys widgets miniPH board. This one stores parameter in eeprom using:

#include <avr/eeprom.h>
#define Write_Check      0x1234

and writes to eeprom like this:

params.WriteCheck = Write_Check;
params.pH7Cal = 2048; //assume ideal probe and amp conditions 1/2 of 4096
params.pH4Cal = 1286; //using ideal probe slope we end up this many 
params.pHStep = 59.16;//ideal probe slope
eeprom_write_block(&params, (void *)0, sizeof(params)); //write these settings back to eeprom

The parametertes stored are thees:

struct parameters_T
{
  unsigned int WriteCheck;
  int pH7Cal, pH4Cal;
  float pHStep;
} 
params;

I think this interferes with mysensosrs eeprom usage.

The whole code of the schetch is here https://github.com/SparkysWidgets/MinipHBFW/blob/master/MinipH.ino

I dont understand what this is referng to:

#define Write_Check      0x1234

Pleas help me
Goran

[AWI]

@goranrad The Write_Check constant is meant to check if there is a valid number written in EEPROM. As the sketch writes from EEPROM adress "0x00" there is good chance that it interferes with MySensors as it uses the same start point
#define EEPROM_START (0u) (defined in MyEepromAddresses.h)

I would advice to rewrite the code to use the MySensors saveState(..) and loadState(..)

[A Former User]

@AWI
Thank you AWI!
I would have to rewrite it like this

write to eeprom would be like this:

saveState(_WriteCheck, Write_Check);
saveState(_pH7Cal, 2048);
saveState(_pH4Cal, 1286);
saveState(_pHStep, 59.16);

read from eeprom would be like this:

params.WriteCheck = loadState(_WriteCheck);
params.pH7Cal = loadState(_pH7Cal);
params.pH4Cal = loadState(_pH4Cal);
params.pHStep = loadState(_pHStep);

do you think this would work?

Then change the WriteState to a int constant with a value of 1234.

Don't know if saveState(..) can store a float or do i have to define it somehow?

Best regard
Goran

[mfalkvidd]

@goranrad saveState can only save a 1 byte value so you won't be able to save integers or floats directly.

You'll need to do something like this, but use saveState instead of EEPROM.write.

[A Former User]

@mfalkvidd
Hi mfalkvidd,

This code takes care of writing to eeprom

#include <avr/eeprom.h>
eeprom_write_block(&params, (void *)0, sizeof(params));

My problem is that mysensors need to handle read and write to eeprom so it dosent conflict with mysensors read and write to eeprom.

Any thoughts on solving this ?

Best regards
Goran

[mfalkvidd]

@goranrad Yes. My suggestion is in my previous post.

[A Former User]

@mfalkvidd I dont understand how http://www.alexenglish.info/2014/05/saving-floats-longs-ints-eeprom-arduino-using-unions/ would make mysensors to take care of the eeprom?

Sorry i'm not seasoned programmer.
/goran

[mfalkvidd]

@goranrad it does if you use saveState instead of EEPROM.write

[A Former User]

thank you!