We would like to utilize ADC inputs on Colibri i.MX6 modules, which are provided by STMPE811 touch screen controller. As we already found out hard way, there are some limitations which we have to consider in hardware design.
Most important is the fact that Analogue Input<1> on Colibri i.MX6 (pin 6 on SODIMM connector) that is connected to pin 9 of STMPE811 is used during reset to select between I2C and SPI interfaces. That effectively means that we have to take care of that during SoM reset and bootup.
Could someone from Toradex specify if there is any pull-down connected to said pin on the SoM module? I am not able to find this information in Colibri i.MX6 datasheet.
Maybe you could include some kind of big fat warning for the Analogue Input<1> in the datasheet? I am not saying that the current documentation is wrong or missing something, but we think that this kind of vital information should be specified directly in the SoM datasheet.
I also believe that STMPE811 Pin Name in table 5-42 should contain values IN0_GPIO0, IN1_GPIO1, IN2_GPIO2 and IN3_GPIO3 instead of all pin names beginning with IN0_ prefix.