MOD-OLED-128x64 Failed

[batoo]

Hello Olimex,

I've a MOD-OLED-128x64, connected to a MOD-IO with UEXT wire.
I can't talk on I2C when the MOD-OLED-128x64 is connected. The SCL and SDA line are blocked to high level (3V3) when i connect the MOD-OLED-128x64.
What's your opinion doctor?

Thanks.

[LubOlimex]

Hey,

Did you consider that MOD-IO doesn't provide 3.3V to the UEXT connectors by default? There are resistors on the 3.3V lines placed there by design (search the schematic for resistors R14 and R16). MOD-OLED-128x64 probably remains unpowered.

MOD-IO has a female and male UEXT connectors. Did the constant high behavior persist among both of them?

The thing is that MOD-OLED-128x64 has i2c pull-ups and the female UEXT connector of MOD-IO also has i2c pull-ups. It might behave better if you use the male UEXT connector (use cable to connect to UEXT-MALE; directly connect the board to UEXT_FEMALE).

These pull-ups might also be affected by other modules attached to the I2C line.

Best regards,
Lub/OLIMEX

[batoo]

Hey,

Did you consider that MOD-IO doesn't provide 3.3V to the UEXT connectors by default? There are resistors on the 3.3V lines placed there by design (search the schematic for resistors R14 and R16). MOD-OLED-128x64 probably remains unpowered.

MOD-IO has a female and male UEXT connectors. Did the constant high behavior persist among both of them?

The thing is that MOD-OLED-128x64 has i2c pull-ups and the female UEXT connector of MOD-IO also has i2c pull-ups. It might behave better if you use the male UEXT connector (use cable to connect to UEXT-MALE; directly connect the board to UEXT_FEMALE).

These pull-ups might also be affected by other modules attached to the I2C line.

Best regards,
Lub/OLIMEX

Oups, i've miss thats, i'll try to powered the MOD-OLED now .
You win a free beer if you come to Toulouse(France), may be for that: http://www.thsf.net
Thank you and have a good day.