What I2C address should I set for this 24LC04 EEPROM?

Using Arduino Programming Questions
1

Hello, I have this project including Arduino Zero's SAMD21G18, and EEPROM 24LC04BT

image

The pins SDA/SCL are connected to ports PA22/23.

In my code, I'm trying to write into the EEPROM using library I2C_EEPROM.

I've started with this code:

I2C_eeprom ee(0x50, I2C_DEVICESIZE_24LC04);
ee.begin();
if (!ee.isConnected())
{
   // error!
}

Sadly, I enter in the error case so I started thinking that the 0x50 address I gave is not correct.
How can I be sure that the address is correct? What should I have to check?

Thanks

2

Run the attched scanner program to know the address of your EEPROM.
i2cScanner.ino (540 Bytes)

3

0x50 is correct (without the ** **)
Is WP connected to ground?

5

0x50 is correct (without the ** **)
Is WP connected to ground?

Sorry, ** was a typo during the copy/paste
WP is connected to GND, this is the full picture

image

I've run the I2CScanner and the output was:

I2C Device found at address: 0x50
I2C Device found at address: 0x51
I2C Device found at address: 0x52
I2C Device found at address: 0x53
I2C Device found at address: 0x54
I2C Device found at address: 0x55
I2C Device found at address: 0x56
I2C Device found at address: 0x57

So I've started to try every address, but I always end inside the error case :frowning:
Should I check other things?

6

If the scanner find it then you have an error in your code.
Post your entire code.

1 Like
7

0x50 is the correct address. Your library has a number of examples that can test your setup. You should first get one of those examples working, then switch to testing your code.

1 Like
8

Please, post the picture of your EEPROM to see how many pins it has.

9

In the IDE click on Edit then on Copy for Forum. That will copy your code. Then come here and just do a paste. No code tags or quotes needed

10

Here is the most minimal code I've tested. The begin() always returns FALSE.
Do you think I should set some GPIOs/peripherals in certain ways before initializing the eeprom?

#include <I2C_eeprom.h>

#define EEPROM_ADDRESS 0x50
#define EEPROM_SIZE I2C_DEVICESIZE_24LC04

void setup() {
  SerialUSB.begin(9600);
  while(!SerialUSB);

  I2C_eeprom eeprom(EEPROM_ADDRESS, EEPROM_SIZE);
  if (!eeprom.begin())
  {
    SerialUSB.println("Eeprom init failed");
  }
  else SerialUSB.println("OK");
}

void loop() {
  // put your main code here, to run repeatedly:

}

Please, post the picture of your EEPROM to see how many pins it has.

Here is it...

image

11

I'm an idiot :slight_smile: I must call Wire.begin() before the eeprom init...

Sorry everyone, thanks for your time!

1 Like
12

Been there.
Glad you got it to work

13

Read the datasheet

What a nice little part with no address legs to worry about whether they float high or whatever.

@misterbirra as @jim-p sez, we all done that. You can sorta go easier on yourself as many things that use Wire do no need the explicit call to its begin() method… I bet there are lotsa ppl who don't even know it's at the bottom of what they are doing.

a7

1 Like
14

Well, I for one have never done anything like that. No. Not once. And I'm sure I never would. I'm never rong.

Indeed

1 Like