GLT240128 RS-232 Touchscreen response issues

LK/ELK/VK/PK/OK/MX/GLK/EGLK/GVK/GLT Series

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heypapadoug
LCD?
Posts: 2
Joined: Fri Mar 05, 2010 9:06 am

GLT240128 RS-232 Touchscreen response issues

Post by heypapadoug »

We are using the GLT240128 in a prototype for a new product. I have multiple screens that I can page thru and have set up an average of 6 touchscreen regions per screen. I have the LCD connected to the hardware RS-232 port on a PIC18F4550 so that I can monitor the data available bit and respond quickly to read in the byte when received. I have set the baud rate to 9600.

One of my issues is that occassionally the LCD responds with the byte from the wrong region. I can verify this by tapping off the RS-232 to a PC and watching what bytes come from the LCD using hyperterm. I have the LCD set to only return the down code for the region (and a code for out of bounds)

Another issue is that when setting the LCD to return the down code and an up code, the LCD does not always return the up code after pressing a touchscreen region. I would like to implement scrolling of a value by holding down on a touchregion, which generally works, but when I don't get the up byte my scrolling does not stop.

Any questions or comments are appreciated.
- Thanks... Doug

Raquel
Matrix Orbital
Matrix Orbital
Posts: 796
Joined: Thu Aug 19, 2004 3:37 pm
Location: MO Office

Post by Raquel »

Hello,

Thank you for posting on the forum.

As the touch screen is resistive, please make sure that when touching, push the screen a little harder, or use a stylus-like pointing device.

As for the the occasional wrong region responses, if you please play some more with the display to hopefully find a pattern to this kind of response. Are your regions close to each other? Also, please double check the region command that you send to the display. Please note that you will need to turn the Remember function on (254 / 147 / 1) when you delete the regions, as I imagine you do when you flip through your different pages. This means that before using commands 133 and 134, you will need to send cmd 254 /147/ 1 once first.

For the up code problem, I will try and see what I can find on the firmware, as it may have a glitch on the algorithm. In the mean time, I suggest that you try the coordinate mode as that also have up code.

I hope this helps. I will get back to you when I find something.

Thank you,
Raquel Malinis
Design and Development
Matrix Orbital

heypapadoug
LCD?
Posts: 2
Joined: Fri Mar 05, 2010 9:06 am

Post by heypapadoug »

Thanks for your reply. Yes, I am sending the remember command (on) before deleting a region or all regions. Unfortunately we can not use a stylus for our application. I have tried varying the pressure parameter. The physical difference is about 1/2 inch between my region boundaries. I can not force it to respond with the incorrect region reference. We have only seen it in our product service mode screen which has more touchkey regions and we are probably more rapidly pressing an up or down arrow key to set an output voltage from our electronics. I can try rearranging the screen display to move the SAVE and EXIT keys further away from the up and down keys.

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