imx6 touchscreen

[小辉哥]

hi，

i am using imx6ul board，I found a very large touch jitter，How can I improve it？my VDDA_ADC_3P3 is connected to DCDC_3V3

Jitter has to do with this？

[art]

Do you use the i.MX6UL on-chip analog touchscreen interface? If so, the answer is: yes, supplying the ADC VDDA_ADC_3P3 supply voltage from a switching DCDC converter (DCDC_3V3) may cause high amount of ADC unstability. To avoid it, follow the original i.MX6UL EVK board connection, where VDDA_ADC_3P3 is supplied form LDO (not switching DCDC converter) produced VLDO_3V3 voltage.

Another point is that for proper ADC operation you have to configure the used ADC input pads (GPIO1_IO00 to GPIO1_IO04) IOMUX as GPIO inputs with pull/keepers disabled.

Have a great day,
Artur

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[小辉哥]

thanks very much！

1，yes i used the i.MX6UL on-chip analog touchscreen interface，ichange the VDDA_ADC_3P3  to LDO，but not very much improved，I found that the larger the screen the more powerful shake。

2，the ADC GPIO configuration as follows：（reference the imx6ul-14x14-evk）