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Other Analog & Touch
I have a question about the TSC2006 Touch Screen Controller.
What is the state of the nPENIRQ pin when there is no touch on the screen?
The pin is programmed as "NPENIRQ and DAV"
Will the pin go "high" despite there is no data available (DAV= "low")?
Please refere to Figure 35 from the datasheet.
At TSC2006, the pin /PINTDAV can be programmed as /PENIRQ, or /DAV, or /PENIRQ and DAV, as stated in the d/s.
If the pin is programmed as the /PENIRQ, it should mainly reflect the statrus of touch on the screen, similar to tha explained in the app article http://focus.ti.com/lit/an/slyt291/slyt291.pdf.
If the pin is setup as the /DAV, it does not bother the host processor even after the touch on the screen, and sends an interrupt (low) to the host only after TSC2006 finishs its all tasks (such touch HW driving, sampling, converting, and filting), a new set (X/Y/Z) of filtered data is at ite data registers, and ready for the host to read. The pin will return inactive (high) after all data regiaters are read by the host.
If the pin is programmed as /PENIRQ and DAV, as you did, the pin go low when the touch is detected on the screen, and go high after TSC2006 finishs its all tasks (such touch HW driving, sampling, converting, and filting), a new set (X/Y/Z) of filtered data is at ite data registers, and ready for the host to read. The pin goes low if the touch is detected again on the screen, mo matter if the data registers have been readed or not by the the host.
Therefore, the /PINTDAV pin does not go "high" if no data avaliable.
Hope I made the answer clear and please feel free to ask if not!
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