TSC2007: Touchscreen reading of 0xA5A5

Mary West34

Part Number: TSC2007

I am using the TSC2007 touchscreen driver. Occasionally, the part returns 0xA5A5 as a response to an 'measure X position' or 'measure Y position' command. I have the part set up as a 12-bit ADC so I would expect values to fall below 4096. Any ideas? Is this an error condition? Any help would be appreciated.

Thanks -

Mary

over 3 years ago

0 Jeff McPherson over 3 years ago

TI__Mastermind 49130 points

Hi Mary,

We are not able to bench test our touch screen portfolio so we appreciate your patience as we work to find an answer for you.

Thank you,

Jeff

0 Brian Donoghue over 3 years ago in reply to Jeff McPherson

TI__Intellectual 2620 points

Hi Mary,

Not sure if your problem ever got resolved, so following up here to check in and give some more info. It's only a 12-bit DAC so it's not possible to get 0xA5A5. When reading back please keep in mind that some bits should be ignored. See this figure from the datasheet.

Brian

0 Mary West34 over 3 years ago in reply to Brian Donoghue

Prodigy 200 points

Hi Brian -

I am only looking at 12 bits. That's why I was surprised to get 0xA5A5. I was just wondering if it was some "magic number". Also, it might be something from the I2C interface.

0 Brian Donoghue over 3 years ago in reply to Mary West34

TI__Intellectual 2620 points

OK, thanks for clarifying. So you are reading 0xA5A5 and masking off the correct bits. Are there any further issues with the device you need help with?

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TSC2007: Touchscreen reading of 0xA5A5