Dunno whether that's you, Andy... anyway, this very strongly suggests the jitter is associated to one PLANE of the ts only (like I guessed quite some time ago). This means: either the "long-axis" X+,Y- rails on powered pane are on the "inside"(near LCD). Touchpoint contacts to the outer plane, and there some sort of hum, EMI, RF, or god knows what is introduced to the relatively highZ "target"plane from environment and is spoiling the A/D for this axis. OR outer and inner plane are reversed (means (+) and (-) rails are on the short parts of outer plane), and the interference comes from our LED-power-converter (or the LCD itself - though I can't imagine this) coupling to the inner plane that goes to A/D-in.
Once more I like to ask whether one of the coder wizards can setup a simple "sample at 500k/s and dump to some file"-type debug helper tiny program, so we might analyze for the real waveform we see on "long axis". We may need this to improve hardware circuitry (filters!) of future resistive-ts designs, as well as to know what we have to tune the ts-lib to cope with for recent devices. A *GOOD* scope probe printout _maybe_ is even better, but this simple A/D-thingy will serve perfectly for a first approach (a least we know for *sure* this is what the A/D-converter (and thus tslib) got) /jOERG
--- Begin Message ---#1194: Touchscreen Jitter ---------------------------------+------------------------------------------ Reporter: [EMAIL PROTECTED] | Owner: [email protected] Type: defect | Status: new Priority: high | Milestone: Component: System Software | Version: unspecified Severity: normal | Resolution: Keywords: | ---------------------------------+------------------------------------------ Comment(by andy): I studied this some weeks ago and also found the jitter is only present on the "tall" axis of the LCM, same as can be seen from cwixon's dump. I cranked up the sample rate in ts platform and it didn't help. So it's still a real problem, not helped to a solution by the ts pins being so hard to probe with a 'scope. -- Ticket URL: <https://docs.openmoko.org/trac/ticket/1194#comment:12> docs.openmoko.org <https://docs.openmoko.org/trac> openmoko trac
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