What are rev E changes ?

[AlCare]

Hello,

We discovered that A20 SOM boards rev E cause i2c issues on our equipments.
rev D worked perfectly.

So I'd like to know what changes have been made on these rev E but unfortunately I cannot find a datasheet mentionning rev E!

Could you please give me the info?

Kind regards.

[LubOlimex]

We added a free EEPROM memory on TWI1 line and that probably affected your equipment. The AT24C16C EEPROM has the downside of blocking I2C addresses 0x50 to 0x57. If your sensor or attachment uses one of these 8 addresses - this would be a problem.

You can find revision changes here:

https://github.com/OLIMEX/SOM/blob/master/A20/A20-SOM/Revision_changes.txt

You can find schematics in PDF here:

https://github.com/OLIMEX/SOM/tree/master/A20/A20-SOM

Probably the change that affected your equipment is this one:

"Added AT24C16C EEPROM on TWI1 line. EEPROM address 0x50. Can cause problems with devices that use I2C1 since it blocks addresses 0x50 to 0x57. The EEPROM comes loaded with production information, refer to this repo for more information: https://github.com/OLIMEX/OLINUXINO/tree/master/SOFTWARE/A20/A20-eeprom-contents"

Hope this gave you idea what might have went wrong.