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Author Topic: Touch Calibration not displaying correctly [SOLVED]  (Read 326 times)

AT38

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Touch Calibration not displaying correctly [SOLVED]
« on: June 26, 2019, 04:27:20 PM »

Hi,

 I am attempting to run the touch screen calibration as per the documentation:

Code: [Select]
(Init screen here)

cmd(DLSTART)
cmd(CLEAR(1,1,1))
cmd(TEXT(80,30,27,OPT_CENTER, "Tap the dot")
cmd(CALIBRATE)
cmd(DISPLAY)
cmd(SWAP)

while(REG_CMD_READ != REG_CMD_WRITE);

This gives me a black screen with a small box of white hash near the top left. (I can post a picture if it would help)
Tapping the screen three times completes the operation, but the transform matrix is wrong because the dots aren't displayed and I've tapped in the wrong places.

The default matrix gives almost the right values, except that it's upside down, so I suppose I could invert param E and it would work,
but I'd like to have the calibration macro working correctly.

I've been having a hell of a time trying to get touch tracking working today, but I don't want to post about that until I've confirmed that the touch matrix is calibrated correctly.

Cheers

 AT38
« Last Edit: July 01, 2019, 09:45:43 AM by AT38 »
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BRT Community

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Re: Touch Calibration not displaying correctly
« Reply #1 on: June 28, 2019, 10:28:28 AM »

Hello,

what Library are you using in you application, for example is it our provided HAL or have you developed your own library?

Yes a picture would be helpful.
Can you grab a SPI trace of when the Display List is written?

Best Regards,
BRT Community
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AT38

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Re: Touch Calibration not displaying correctly
« Reply #2 on: June 28, 2019, 05:41:36 PM »

Hi,

 Thanks for your reply. I figured out the problem as I collated data.
 I was sending the parameters for the text command as 32bit instead of 16bit.
 The hash on screen was the text command reading out from an invalid bitmap cell and then falling over.
 Probably corrupted the display list after that, hence no dots, but still accepting touch input.

 I'm developing my own library, fyi.

Cheers,
AT38
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