Have I to use an I2C pin to write into EEPROM ?

[STM32L0Fan]

I ask this question because I am already using all the i2c pins for my lcd screen and I need to write in EEPROM and it seems that I need to configure a I2C to use the hal function to write ...

[Mike_ST]

Hello,

If you have an I2C EEPROM in your design, you'll have to configure an I2C instance to communicate with it.

[STM32L0Fan]

I saw that it was maybe possible to use a SPI pin, do you know if it is possible to write/read eeprom with SPI ?

(thank you for your first answer btw)

[Andrew Neil]

@STM32L0Fan​ : "do you know if it is possible to write/read eeprom with SPI ?"

That depends on the EEPROM:

• if it's an I2C EEPROM, then you can only read it with I2C;
• if it's an SPI EEPROM, then you can only read it with SPI;
• some EEPROMs can work with both SPI and I2C

You will have to study the documentation for your EEPROM to find which applies ...

[Mike_ST]

1) SPI is not I2C.

2) There is solution to simulate I2C using 2 GPIO. google "STM32 software I2C", hopefully you'll find something.

[LMI2]

Besides, an I2C bus can be connected to more than one devices/slaves. I2C devices have addresses, so that it is possible to know what device you are currently using.

[Andrew Neil]

As @LMI2​ said, I2C is a bus - the whole point of a bus is that multiple devices can share it. That's why it has addresses.

You don't need a separate I2C for each peripheral:

https://en.wikipedia.org/wiki/I%C2%B2C

https://learn.sparkfun.com/tutorials/i2c/all

https://learn.adafruit.com/i2c-addresses

https://www.i2c-bus.org/

https://www.nxp.com/docs/en/user-guide/UM10204.pdf

[STM32L0Fan]

Ok thank you for your answer, the answer to my issue is that with the hal function : HAL_FLASHEx_DATAEEPROM_Program() you can do what I wanted to do.

[Tesla DeLorean]

That would suggest you're using an STM32L0 part, with an Internal EEPROM, not an external one using I2C or SPI