We are using the STMPE811QTR touch screen controller in a project and observed unexpected behavior during testing. Specifically, the device's touch functionality became disabled temporarily and then recovered. To replicate the issue, we shorted the A0/Data Out pin (Pin 3) to the ground, which caused the touchscreen to fail. Power cycling the device immediately after the failure did not resolve the issue. However, the device recovered after being in the OFF state for approximately 17 seconds. Further investigation revealed that this recovery time corresponds to the time required for the IC's VCC (6V), Vio (pin 14) pin voltages to decay.
We have implemented a 4.7 µF tantalum capacitor and a 0.1 µF ceramic capacitor as decoupling capacitors. Upon removing the tantalum capacitor, the recovery time decreased to approximately 4 seconds. Please refer to the attached schematics and provide any insights or suggestions to help avoid the device recovery period caused due to the touch screen failure.
Note:
1) The I2C_ADDR0 signal comes from the MCU side (STM32F429IIT6).
