TSC2008-Q1: TSC2008TRGVRQ1

Ramgopal Divakar

Part Number: TSC2008-Q1

Tool/software:

Hello,

was are using TSC2008TRGVRQ1 and our prototypes worked pretty well. I am now seeing a lot of noise on the IRQ line and it is locking up the microprocessor. We found the cause as our speaker in the front panel that shares the touch screen. Moreover, the PWM driver of the speaker goes via a pi-filter which connects to the chassis.

Overall, a combination is causing it.

I read in the datasheet that we can add capacitors to the 4 pins. What value do you recommend as a start? Please see my circuit below.

1 month ago

0 Sanjay Dixit 1 month ago

TI__Mastermind 22820 points

Shall reply shortly today.

0 Sanjay Dixit 1 month ago in reply to Sanjay Dixit

TI__Mastermind 22820 points

Does the speaker have long Cables? Sometimes these can radiate the PWM switching to the inputs of the Touch Screen Controller.

Alternatively the issue can be poor earthing of the Touch screen controller. Do you have a possibility to move the board of the touch screen controller at a distance from the Amp circuits to see if the interrupts reduce? This wil help to isolate if this is a radiation or conduction issue.

0 Ramgopal Divakar 1 month ago in reply to Sanjay Dixit

Expert 1145 points

I was able to fix it by adding 0.01 uF from the 4 pins X+, X-, Y+, and Y- that your datasheet suggests - Adding caps. However, after the calibration is a little mssed up. The return coordinates are non-linear. Do I need more than 2 point calibration?