set a different i2c address for MOD-LCD2.8RTP

[mihaiadrian]

Is it possible to set a different i2c address for touch for MOD-LCD2.8RTP ?

thanks and regards,
Mihai

[LubOlimex]

I don't think so, I am looking in chapter "4.3 Addressing" in the datasheet of the touch controller AR1021 and I can't see address change option; document can be found here:

https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/DataSheets/40001393C.pdf

7-bit address is 0x4D and 8-bit addresses are - write address is 0x9A while read address is 0x9B

[mihaiadrian]

I checked also for NS2009 - same. Some other chips had some jumper or something to set/flash a sliglty different address, here I see nothing. So seems is not possible.

Any ideea, on esp32-poe-iso   could I use GPIO:  0, 1, 3, 35, 33, 32   for  as i2c communication channels ?   I plan to use esp32-poe-iso with cable network, with one bme280 sensor and 3 additional displays ( for the displays I have a solution to connect, but not for touch which are on i2c - so this is why I opened the topic ). Touch is even worse, because, if 2 touch devices are connected ( using same i2c address), none is working.

Another solution would be to use touch only on 1 display - but, in this case I would have to find a way to cut the power from the touch controller for the other 2  - to avoid consumming  0.1w for doing nothing ...

esp32-poe-iso map here:   https://www.olimex.com/Products/IoT/ESP32/ESP32-POE-ISO/resources/ESP32-POE-ISO-GPIO.png

[LubOlimex]

I would personally avoid GPIO0 and GPIO1 since this might bug the communication over the USB and further programming. Also these two will behave "interesting" after hardware reset.

It might be better idea to check the schematic PDF to track pins instead of the GPIO image.

You might consider touchscreen with either different address (meaning different touch controller chip) or different interface if there are free pins.

[mihaiadrian]

thank you, just tested now, I can use GPIO 0 and 1 for CS/SSEL for SPI for 2 displays and works very well, also flashing seems to not be impacted.   Don;t know about the rest GPIO's, I have not tested yet.

[mihaiadrian]

I would personally avoid GPIO0 and GPIO1 since this might bug the communication over the USB and further programming. Also these two will behave "interesting" after hardware reset.

You were right, GPIO1 impacts USB debug communication. I will have to avoid it.