View Full Version : 17" touchscreen works with Propeller Demo board and VNC2

03-12-2012, 06:25 PM
This is just a tip, in case anybody wants to use a reasonably priced VGA touchscreen...

Just did some initial testing with: TRIVIEW by Tatung TS17R-02 Black 17" Dual serial/USB ELO 5-wire Resistive Touchscreen Monitor
and it looks like it will work nicely. It's $349 at NewEgg.com

Ran my usual 1024x768 VGA output and that syncs up fine.

Also used my Vinculum2 V2DIP2-32 device plugged onto the Proto area to get touchpanel info.
See this thread for a photo: http://forums.parallax.com/showthread.php?135775
Just some simple changes to their USBHostHID code makes it work with no handshaking, so I just need 1 Prop pin to receive data.

Here's the data format:

'Output when touching various areas:
'byte: 1 2 3 4 5 6 7 8
'top left: 54_04_DB_01_8A_0D_00_00
'top right: 54_01_EB_0D_8B_0D_FF_00
'bot left: 54_01_EB_01_06_02_FF_00
'bot right: 54_01_EE_0D_09_02_FF_00

'1: always $54
'2: 01: Initial touch; 02: Stream touch; 04: Untouch.
'3: Xlo
'4: Xhi
'5: Ylo
'6: Yhi
'7: $FF when touched, $00 when released
'8: Always $00

I suppose you could also use the regular DB9 serial output, but this way is more fun :)

BTW: I also tried the Acer T231H 23" widescreen touchpanel, but it didn't cooperate right away with the VNC2 (and only has USB output).

03-12-2012, 07:32 PM
Awesome work once again Rayman.

Pity about the Acer T231H, those are the ones available here for a reasonable price ($373). There are also LG models 17" ~ 19" and these are more like $600

03-12-2012, 11:14 PM
Another Gold Star for Rayman. Keep up the good work.

I'd be interested in your thoughts on resistive vs capacitative touchscreens.

03-13-2012, 03:34 AM
Just some simple changes to their USBHostHID code makes it work with no handshaking, so I just need 1 Prop pin to receive data.

Which VINC2 library did you use, and I guess that was not a hardware handshake but a Query based request ?
If you run single pin, at what repeat-rate does the VINC2 report at, and what baud ?

With a single pin, you would need to tolerate half-packets, which is not hard.

03-13-2012, 09:42 AM
I just used their GUI development tool. I've got no idea what library that is...

But, it appears to me that all HID type devices give "reports" when something changes...
When you press a key on a keyboard or move the mouse, you get a report.

This touchscreen gives you a report when first pushed and then continously streams out reports while pressed and then one final report once you lift your finger...

But, turning on a status LED on a keyboard requires you to send data the other way, so I would need 2 pins in that case.
(Haven't tried to do this yet...)