hello,
I am working on tinylcd's 3.5 TFT Lcd with touch screen, the lcd is working fine but the touch is not working properly.
the part number of lcd is TL03503200480E. Any help would be greatly appreciated.
thank you
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hello,
I am working on tinylcd's 3.5 TFT Lcd with touch screen, the lcd is working fine but the touch is not working properly.
the part number of lcd is TL03503200480E. Any help would be greatly appreciated.
thank you
As you note the "Lcd" as "Tiny" - might your "Not so Tiny" finger - confuse/confound the screen's "Touch-Sense" mechanism?
it is usual that such screens require strategic, "drive signals" in which "Only one touch plane is Enabled for "READ"" - while its orthogonal "neighbor" is voltage driven - such that the "touch plane" may be read.
After a given interval that situation (almost exactly) reverses - and the 2nd screen is then "read."
This is (highly) unlikely to be an MCU based challenge - it is (very much) an LCD Vendor issue - they should receive your (probing/questioning) report...
You haven't noted the "type" of touch screen - there are several types. I'd suspect that yours is "Resistive" - an upgrade would be "Capacitive" - yet that's usually more expensive - and more difficult to control.
You note "SPI" as the interface for the display - yet there (still) is no mention of the "interface to the Touch Screen." (You clearly can touch/see your device - we helpers do not have that luxury - we "rely upon you to properly describe" - & provide such (needed) facts.
You write, "During calibration ... when you touch it ... "it IS getting calibrated." Yet - "How do you know that?" Most such "calibrations" require a minimum of three "Touch Points" - sometimes that extends to five.
After such "calibration" - the effectiveness of that calibration is gleaned by your "Touching" several strategic screen points - and then confirming that the Touch Data supplied - is w/in specification. As you cannot (yet) "Read your Screen" - it is difficult to justify your claim of "proper calibration!"
Most Resistive (low cost) such screens employ a "four-wire interface." You should be able to "follow the tiny (and transparent) "ITO" traces - and identify the four Touch Interface signal entry points. (most always 2 will attach to the "left & right" screen edges - the other 2 attach to the "top & bottom" edges.)
You may monitor those 2 signals (vertical or horizontal) - noting that one signal will "switch to ground - the other will supply source voltage." And - as stated earlier - these signals will "cycle" - with (at any particular time) one pair being voltage providing - the second pair providing an analog voltage - reflective of the (actual) screen touch point.
Now you may have a "Touch Controller" - but if the screen is Resistive - it MUST work as just detailed... The Touch Controller will "intercept" the analog voltage from the "Non-Driven Plane" - and output that via (usually) a serial interface. It then "becomes your job" to "Read the Touch Controller" which should provide (both) "X & Y" Plane position info.
While it IS tempting to "purchase" highly discounted devices - such vendors rarely display the required "skill or caring" - which "Drive your project to Success!" (And it is likely that you'll "never/ever" be able to buy that "exact" screen - again...)