Other Parts Discussed in Thread: TCA9539
I am trying to use the IO Expander EVM board to test the aforementioned gpio expander. I do not have the MSP430 Launch Pad board that the datasheet for this EVM says is required, nor do I want it. I am attempting to test this expander chip for one of our designs by using a radxa rock 3b and connecting it to the SDA and SCL pins on the EVM. I am also powering the EVM with the 3b board.
I have managed to use i2c commands on the command line to turn gpio pins to inputs and outputs, thereby lighting the LED's on the EVM that are attached to their respective GPIO pins. But I am running into two problems:
1. Without being able to use the GUI, how can I select which expander I am using within the U2 chip on the EVM? I would imagine there is an i2c register that I could set to select this.
2. P00 and P01 are not lighting their LED's when I set their configuration to output. I set the jumpers on the EVM to "out" as stated in the datasheet, but the LED's still never light up, telling me that they are not being set to output.
As a note, not much of an issue, just an oddity, the device address for the expander I am currently testing (which i assume is TCA9535 since it is the default selection in the GUI screenshots in the datasheet) seems to be 0x77, which is not a possible address according to the TCA9535 data sheet.
