IL9341 Soft reset

[cezar]

Hi all,

I'm designing a little thing with IL9341 TFT display and ESP8266. I'm trying to save a couple GPIOs for further use. I have pulled the TFT RESET PIN high and I'm trying to use soft reset command 0x01 but it does not seem to be working. The display works fine when is powered up but If I reboot the ESP, it gets stuck on what was displayed before.
Does anyone have any experience with soft resetting it?     
for reference:

https://cdn-shop.adafruit.com/datasheets/ILI9341.pdf

[mikerj]

Soft reset is not a replacement for the hard reset.  From the datasheet

12.1. Case 1 – RESX line is held High or Unstable by Host at Power ON
If RESX line is held High or unstable by the host during Power On, then a Hardware Reset must be applied after
both VCI and VDDI have been applied – otherwise correct functionality is not guaranteed. There is no timing
restriction upon this hardware reset.

[HB9EVI]

I started to join the reset pin of the ILI9341 with the reset pin of the mcu driving it properly on power up, and so far I had no problem with the soft reset, which is part of the init routine.

some code could help finding the issue

[cezar]

Soft reset is not a replacement for the hard reset.  From the datasheet

12.1. Case 1 – RESX line is held High or Unstable by Host at Power ON
If RESX line is held High or unstable by the host during Power On, then a Hardware Reset must be applied after
both VCI and VDDI have been applied – otherwise correct functionality is not guaranteed. There is no timing
restriction upon this hardware reset.

The display works completely fine after the power on. It gets stuck when I reboot the MCU (and doing soft-reset from the code)

[cezar]

I started to join the reset pin of the ILI9341 with the reset pin of the mcu driving it properly on power up, and so far I had no problem with the soft reset, which is part of the init routine.

That's a good idea. I'll test it out

some code could help finding the issue

For the prototype, I use the Adafruit_ILI9341 library.
I basically issue

Code: [Select]

tft.begin();
It should do soft reset when tft is initialised with rst declared as -1

Code: [Select]

if (_rst < 0) {                 // If no hardware reset pin...
    sendCommand(ILI9341_SWRESET); // Engage software reset
    delay(150);
  }