# Resistive touchscreen with 5-wire connection & Freescale IMX28

I have a IMX28EVK board and I would like to to connect this board to a 5-wire resistive touchscreen.

In the Reference Manual of the I.MX28, Freescale said:
LRADC 2 - 6 can be used for 4/5-wire touch-screen control. LRADC 6 can be used for the wiper of 5-wire touch-screen controller and external temperature sensing, but they cannot be enabled at the same time in hardware configuration. LRADC 5 can be used for Y- of 4-wire and LR of 5-wire; LRADC 4 can be used for X- of 4-wire and UR of 5-wire; LRADC 3 can be used for Y+ of 4-wire and LL of 5-wire; LRADC 2 can be used for X+ and UR of 5-wire; For pull-up or pull-down switch control on LRADC2~5 pins, please refer to HW_LRADC_CTRL0 register.

I think that there's an error. The word UR is repeated 2 times and UL never appears

I have this touchscreen:

Model: EL-TS-104F-5H Type: Analog resistive 5 wire B-type.

This touchscreen has 5 pin:

1 - RT; 2 - RL; 3 - SG; 4 - LT; 5 - LL

|----------|
|LT      RT|
|          |
|LL      RL|
|----------|


RT <-> UR
RL <-> LR
SG <-> wiper
LT <-> UL (?)
LL <-> LL


But the touchscreen doesn't work properly. Is the connection that I've made is correct? If not, what's the right connection? Any suggestions?

-
I've got the same EVK and a custom board based on the MX283. (No LCD or touchscreen, however) What steps did you take in LTIB or kernel configuration? You may need to look at the linux/arch/arm/mach-mx28/ platform files and modify the LRADC configuration that way. I'm assuming you have a working LCD? Most likely, the Freescale MX forum would be better for this question. – darron Jun 9 '11 at 18:28
I have the evk and my custom board. I also have the evkLCD with touch (4-wire) and another LCD with touch (5-wire).<br> No problem with LCD, all working properly, also the 4-wire touch.<br> I think that LTIB is configured right, but is possible that I was wrong.<br> Do you think that is possible that the LTIB is configured for only 4-wire touch and not for 5-wire? However i will go check the platform file. <br> Thanks for the hint.<br> – Katte Jun 10 '11 at 6:42
Ok, probably I need to reconfigure LTIB. Maybe I need to use a different driver or to create a new one.. Thanks for the hint. – Katte Jun 10 '11 at 7:09
is this reference manual online? And if so could you provide a link? Thanks! – dhsieh2 Jun 19 '11 at 16:32