Got my touchscreen overlay and controller - now what????????

notion · 09-16-2002, 06:02 PM

After dealing with Milesie.co.uk I'm left with a less than pleasant taste in my mouth. They took my order without telling me they were out of stock, when they eventually shipped the unit they used the cheapest possible shipping so it took nearly 2 weeks to arrive. Plus when I opened the package there was no documentation or software included - just parts.

Anyway, at least the parts look good, the controller is driven by an RS232 interface, so my first question is....

How do I connect the RS232 inteface of my controller to my Via Eden 800 motherboard which will be located at least 6 feet from the screen????

Secondly, the controller runs on 5v, I have 7.5 volts supplying my display already, what is the easiest way to leech a feed from that supply and get it down to 5v for the controller???

Please bare in mind that I am a box whore and have no idea about electronics, I just plug stuff together.

Joel

brooksy69 · 09-27-2002, 06:54 AM

read thi swith interest - pretty good prices for touchscreen. just wondering how you are getting on with this problem?

blowback · 09-28-2002, 06:55 AM

have the same setup - or will have when the damn touchscreen arrives (and I live in the same country as Milesie!) I'll let you know how it goes.

Shame there's no documentation, but AFAIR you hook the controller board up to the serial port.

Charliey · 09-28-2002, 12:05 PM

RS232 is a serial port connection, so you'll connect it to your mother with a serial cable going into the serial port.

I dont know much about software though.

For the 5v for power, you could just take it from the 5v line in the computer power supply.

Electronicsuk · 09-28-2002, 12:54 PM

A 7805 regulator would do that nicely. Has 3 pins, input, ground and output. Changes from 6.5-40v DC to 5v DC.
Best regards,
Matthew

blowback · 09-30-2002, 12:35 PM

OK, I just received the V16 controller and a RES-5.7-PL4 resistive touchscreen from them.

As in your case, I received nothing in the way of documentation, but I pestered them and managed to get this pinout diagram for the V16 controller.

blowback · 09-30-2002, 12:39 PM

In addition you can find tech docs on the touchscreens at www.microtouch.com which is now owned by 3M.

There's a bunch of useful stuff on there, including the mechanical drawing for this screen (giving the pinout) attached below.

One of the documents I read there suggested that the orientation of the connector between the touchscreen and the controller card is not important.

The chip used on the V16 board is a Dynapro 95705, although I could find no useful info on http://www.dynatouch.com/ which is again owned by 3M.

What concerns me is that some of the technical docs mention calibrating this setup, yet without any kind of documentation for the controller or its chip it isn't clear how this is achieved.

I'll let you know how I get on trying this combo out tonight.

blowback · 09-30-2002, 04:02 PM

Heh, I really need to stop talking to myself

Anyway, a bit of further research has revealed that the Miles Industrial V16 controller is actually designed by a UK company called VisComm. They won't give much detail, but they've assured me that the 95705 chip on the V16 board is actually a Dynapro SC3 serial convertor chip, for which numerous drivers are available on the website, including an XFree86 one.

I think we can safely assume that the V16 board is therefore not a million miles away from the SC3 reference design.

FYI it's a 2400 baud serial interface, 8 data bits, no parity, 1 stop bit.

This document has a fair few details on programming and interfacing it.

streetpower · 09-30-2002, 07:58 PM

Just thought id give you a thumbs up for some great utilization of the internet there, this is very good info.

blowback · 09-30-2002, 10:19 PM

Ok, I finally got this working after much fiddling about. Here's how to duplicate my setup.

Firstly, the serial connectionto the PC. You have to connect header J2 on the controller board to the PC's serial port. I did this by hacking off one of the connectors from the supplied cable which had identical 2x5 connectors on each end and replacing it with a female DB9 connector.

J2 looks like this:

1 2
3 4
5 6
7 8
9 10

Of these pins, only 3 need to be connected:

PIN 3: connect to DB9 pin 3 (data from controller to PC)
PIN 5: connect to DB9 pin 2 (data from PC to controller)
PIN 9: connect to DB9 pin 5 (signal ground)

The V16 controller is thus wired as a 3-wire DTE. Remember that the serial settings are 2400baud, 8N1, no handshaking (although you can change the baudrate in software).

Next up, you need to connect the touchscreen. I can only assume that the cable which Miles Industrial supplied me is for 8-wire screens or something, coz it's completely bloody useless for my screen, which is a 4-wire interface.

The controller card interfaces to the touchscreen with two headers, J1 and J4. Only J4 is used for a four wire interface. From top to bottom, J4's pin assignments are:

pin 1: YE-
pin 2: YE+
pin 3: XE-
pin 4: XE+

For reference purposes, J1 is:

pin 1: YS-
pin 2: YS+
pin 3: XS+
pin 4: XS-

For an 8-wire interface you'd use both J1 and J4. For a four wire interface such as I have, you use J4 only.

The connector from the touchscreen itself has an arrow by pin 1, and the connections in order are:

pin 1: TOP
pin 2: BOTTOM
pin 3: LEFT
pin 4: RIGHT

As far as I can tell from the diagram of the touchscreen, TOP corresponds to YE-, BOTTOM to YE+, LEFT to XE-, and RIGHT to XE+, although it doesn't actually matter as the calibration phase of the software can figure out the orientation.

The cable I was supplied with was an 8 way one with a 2x4 connector on one end and a 1x8 connector on the other.

The 2x4 connector straddles both J1 and J4, so for the cable, the pin assignments are:

1: J1 pin 1 (YS-) 2: J4 pin 1 (YE-)
3: J1 pin 2 (YS+) 4: J4 pin 2 (YE+)
5: J1 pin 3 (XS+) 6: J4 pin 3 (XE-)
7: J1 pin 4 (XS-) 8: J4 pin 4 (XE+)

the touchscreen is expecting 1:YE-, 2: YE+, 3: XE-, 4: XE+, so I had to rebuild the 1x8 connector so that the relevant signals went to the right places. In detail, I moved pin 2 to pin position 1, pin 4 to pin 2, pin 6 to pin 3 and pin 8 to pin 4. I hope the attached photograph illustrates this better. Sorry about the composition, but hey it's 3am here

So I'm now in a state where my terminal software can quite clearly see the controller reporting movement on the touchscreen. I haven't tried it with 3M's drivers (coz I need to write my own linux DirectFB driver for my project), so I can't verify that the horizontal and vertical connections are the right way round, but like I said, calibration should sort this out.

Apologies for the long post, but hopefully it helps somebody out.