Unable to get correct calibration results

nitesh chowdhary

Other Parts Discussed in Thread: ADS7843, ADS7846

Hi,

I am using ADS7843/XPT2046 (SPI based touch controller) interfaced with AM335x custom board, i am trying to calibrate the LCD using "ts_calibrate" tool in linux, but what i observed that we are not getting the normal results as shown in below figure 1. We are able to get results as shown in below figure 2. So is there something wrong with the hardware connections.??

We are currently using Waveshare LCD.

http://www.wvshare.com/product/4.3inch-480x272-Touch-LCD-B.htm

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|(Xmin, Ymin)                                            (Xmax, Ymin) |
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|(Xmin, Ymax)                                           (Xmax, Ymax)|
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                                   figure 1

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|(Xmin, Ymax)                                           (Xmax, Ymax)|
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|(Xmin, Ymin)                                         (Xmax, Ymin) |
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                                   figure 2

regards

Nitesh

over 9 years ago

0 Andy Liu (BMS) over 9 years ago

TI__Guru 52115 points

Hi Nitesh,

Have you tried the test program "ts_test" from tslib after calibration? Could you see correct trace when you run this test program?

Andy

0 nitesh chowdhary over 9 years ago in reply to Andy Liu (BMS)

Intellectual 460 points

Hi Andy,

I did tried the test program "ts_test", but i was not able to get the correct trace.

I resolved the problem, by making below changes in the driver , i was able to get correct pattern (figure 1) with "ts_calibrate"

Original:

 input_report_abs(input, ABS_Y, y);

Modified:

 input_report_abs(input, ABS_Y, (4095 - y));

regards
Nitesh

0 nitesh chowdhary over 9 years ago in reply to Andy Liu (BMS)

Intellectual 460 points

Hi Andy,

I did tried the "ts_test" program, but was unable to get the correct trace.

I resolved the problem by making below changes in the ads7846.c linux driver, i was able to get the correct pattern (figure 1) with "ts_calibrate".

Original:
input_report_abs(input, ABS_Y, y);

Modified:
input_report_abs(input, ABS_Y, (4095 - y));

regards
Nitesh

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Unable to get correct calibration results