Dear all,

I am having problems using my 2.4" touch screen on an ESP8266 -12 module using I2C. Writes work fine, but I cannot read from tehe module.

The touch works perfectly on an Arduino UNO using I2C but when the code is ported to an ESP8266, the touch read function (readTouchScreen()) hangs the processor.

For completeness, I am using the WeMos ESP8266 D1 Mini board and have 4k7 pull-up resistors on both SCL and SDA lines.

Has anyone had this problem and found a solution??

Many thanks,

... Adrian

 Check the R2 resistor which mark as 4.7K near by the MCU on the PCB, short this resistor, will make the MCU to handle the SDL signal.
If this is not work for you, please use the PENIRQ pin, this pin will be pulled to low when touch screen pressed down, your ESP8266 can quote this pin to determine the touch screen pressed.
 

Thanks for your reply.

The touch screen works on an Arduino. So are you suggesting that I make a hardware change to the board to get it to work with the ESP8266?

Service,

Can you please respond to my question? 

Do I really need to make a hardware change to the display just to have it run on an ESP8266?

Is this something to do with operating the I2C interface at 3.3v?

Thanks,

... Adrian

The problem is in the I2C lib for ESP8266, the I2C read function can't wait too long (typically 432 us) to slave prepare the data, and exit without error, we solved this issue by modify the I2C lib for ESP8266.

http://www.digole.com/forum.php?topicID=777