• Resolved

TSC2046E X and Y Data Interacting

We are using the TSC2046E to read a 4-wire resistive touch panel and using the internal reference..

The TSC2046E is being driven by an FPGA. We are using commands 0x93 and 0xD3 to read the x/y position (we also tried 0x90 and 0xD0). The TSC2046E with this FPGA code worked fine on the previous board but on this board, changes on one coordinate effect the other coordinate. There are no changes between boards in area the TSC2046E circuit other than a change on the pins used to connect the FPGA to the TSC2046E. We have looked at the signals in the FPGA using SignalTap and verified that they look correct. We have scoped the pins on the TSC2046E and verified that they have the same signals that we see in the FPGA.

We tried substituting resistors for the touch screen and got different readings when the 3 resistor net was connected to X+ Y+ X- and Y+ X+ Y- (e.g. the X and Y readings did not swap when the resistor nets were connected across the associated inputs)

Note, there is a typo on the schematic, C222 is 10nF, just like C221, C223, and C224.