Power Supply problem on TFT LCD

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#1
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Hi all,
I've got a problem with TFT LCD with ILI9320Controller,
Sometimes disconnecting the power supply and then connecting that after nearly 2 seconds results in malfunction , in a way that there nothing could be seen on the screen.
By the way I don't have this kind of problem with TFT LCD with SSD1289Controller .
What's the problem ?

Thanks in advanced

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Do you really expect us to come up with an answer to such a nebulous question?
What tft lcds are we talking about? When you disconnect the power supply - power supply to just the lcd? Or the complete circuit? What happens if you disconnect the power for less than 2 seconds? More than two seconds?

My guess - check the reset circuit and read the datasheet.

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Sorry , I’d heard having this kind of problem is something usual and maybe … ,
Ok :
Module : HY32D
Touch IC : XPT2046 (PIN COMPATIBLE WITH ADS7846)
Controller : ILI9320 Or SSD1289
Disconnect the power supply from the circuit
For less than 2 seconds it works correctly (Showing the bitmap on the screen)
More than 2 seconds there is malfunction (Nothing could be seen on the screen)
But this 2 seconds is not exactly 2 seconds , it maybe more or less and sometimes there is no problem at all . I have to repeat connecting and disconnecting the power supply for sometimes 50 times to see the problem and it maybe working correctly for 50 times

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To fix this, you need to know what every bit in every byte written in the init routine does. You need to look in the datasheet and decide how to set every bit in every register. Some will be dontcares, but you need to decide whether or not they can be ignored. Somebody did about 85% of this in the example init, but he probably just copied the init from some other chip that was ALMOST the same. He almost got it right didn't he?

Imagecraft compiler user

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Thanks ,

To fix this, you need to know what every bit in every byte written in the init routine does.

Yes that's right , but there are lots of different registers and it needs at least 1 week to completely verify the datasheet and unfortunately at the moment I don't have this time . But yes I have to do that as soon as possible

I replaced 1uF CAP instead of 100nF in the power on reset of the microcontroller and the problem is solved now .

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My guess regarding the reset circuit was close. Look at the specs regarding startup time and make sure they're being obeyed.