MityARM-335x I2C1_SDA and I2C1_SCL Pull-up Resistors
Added by Joel Minski about 11 years ago
It appears that the I2C1 pull-up resistors are placed on the DevKit (connected to the +3.3VDVI net) and not on the MityARM module itself. This seems to be an oversight/error since the I2C1 bus is also connected to the module's on-board EEPROM and PMIC.
Since we did not realize this and neglected to bring out the I2C1_* pins on our carrier board design, are there a set of test points on the MityARM module that we can add pull-up resistors to for the I2C1_SDA and I2C_SCL lines? Or do we need to flywire to the pins on the socket?
Any other suggestions?
RE: MityARM-335x I2C1_SDA and I2C1_SCL Pull-up Resistors - Added by Michael Williamson about 11 years ago
I am looking at the schematic for the SOM, and there are 4.7K Ohm resistors on I2C1_SCL and I2C1_SDA to VDDIO (+3.3V). There also 4.7K pullups on I2C2_SCL and I2C2_SDA. Both I2C ports are connected to the PMIC. I think that the DevKit resistors may have been put on in error (though the shouldn't cause too much trouble).
Are you certain that there is a problem here?
RE: MityARM-335x I2C1_SDA and I2C1_SCL Pull-up Resistors - Added by Joel Minski about 11 years ago
Thanks for clarifying how the I2C buses are implemented on the module.
There is no problem, I was unclear on how the I2C buses were used on the module and was misinterpreting a kernel debug error message.