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Interfacing Sharp LM64121K from Psion Series 5 Palmtop
http://forum.lcdinfo.com/viewtopic.php?f=6&t=1137		 Page 1 of 1
Author:  new299 [ Thu Mar 31, 2005 23:56 ]
Post subject:  Interfacing Sharp LM64121K from Psion Series 5 Palmtop
Hello,

I'm trying to interface a Sharp LM64121K display from a Psion Series 5 Palmtop. I can't find a datasheet for this part, but by examining how it's interfaced in the palmtop I've come up with the following:

|| Pin || Purpose
|| 01 || Digitiser
|| 02 || Digitiser
|| 03 || Digitiser
|| 04 || Digitiser
|| 05 || GND? digitiser
|| 06 || 3.2v
|| 07 || 20v
|| 08 || 18.5v
|| 09 || 1.5v
|| 10 || 17v
|| 11 || 3v
|| 12 || GND?
|| 13 || CL1
|| 14 || CL2
|| 15 || DD[0]
|| 16 || DD[1]
|| 17 || DD[2]
|| 18 || DD[3]
|| 19 ||
|| 20 || FRM
|| 21 || M
|| 22 || appears to be GND, shorted to connector

What I'm wondering is if someone could tell me if this looks about right? Are 20V voltages common for this type of display? The values on pins 6-10 were just found by sticking a multimeter on the device.

If I will need to do this, can anyone suggest the easiest/smallest number of required components to do this?

Many Thanks,

Nav
Author:  Henri [ Sun Apr 03, 2005 11:33 ]
Post subject: 
20V sounds normal.

You didn't mention what you'd like to interface this with ?

Looking at the pinout it has 4-bit parallel data input and the normal scanning inputs so a controller like S1D13305 for example could work.
Author:  new299 [ Sun Apr 03, 2005 18:33 ]
Post subject: 
OK, thanks very much. Is there a DC-DC convertor IC available that will convert 3->5V DC to 20V?

I'm not sure about interfacing yet, will look into the controller you suggest.

Many thanks,

Nav
Author:  Henri [ Thu Apr 07, 2005 22:00 ]
Post subject: 
Here are some circuits worth checking: http://forum.lcdinfo.com/viewtopic.php?t=63

MC34063 should work too.

When you decide what kind hardware you would like to interface the display with you can post that too as the application where it would be used can be important in determining the best ways to do things.
Author:  juliosilva [ Sat Jan 28, 2006 4:02 ]
Post subject: 
Hello

Did you make it?

I'm looking for some data to use onde PSION S5 Display too.
Can you give me some hints?

Thanks,

jS
Author:  new299 [ Sat Jan 28, 2006 13:44 ]
Post subject: 
juliosilva wrote:
Hello

Did you make it?

I'm looking for some data to use onde PSION S5 Display too.
Can you give me some hints?

Thanks,

jS


Yes and no, I managed to get the display hooked up to a gumstix (ARM single board computer) using thepinout/timings above and it works fine. But I never got round to figuring out how to power it, part of the problem being I wanted it battery powered. I'm still interested in the project, and have been thinking of trying to buy some DC->DC convertor modules that do all the hardwork for me, maybe from Farnell?. Alternatively, if someone wants to make me a couple that give the right voltages I'll happy pay 20quid or so. :)
Author:  Ed_Ca22 [ Mon Jul 24, 2006 19:34 ]
Post subject: 
I am looking to do exactly what you have done and have some questions; did you interface directly to the gumstix or using a controller? Could you give me details of the hardware/software implementation? Was it difficult to get Linux to work with the LCD? I will try to find a suitable step up converter - have you tried investigating how it was done on the Psion itself?

Did you get the digitizer working? Any ideas on how to interface to it? Is it just a pair of ADCs?

Thanks for any help you can give,

Cheers,

Ed.
Author:  Henri [ Wed Jul 26, 2006 19:01 ]
Post subject: 
XScale has a built in lcd controller. It's not difficult to configure it for different panels in Linux. This should be documented somewhere in the framebuffer driver sources in the kernel.

For some explanation of touchscreens you could check this application note from Sharp: http://document.sharpsma.com/files/LH7x ... screen.pdf
It's meant for the Sharp controllers with on chip touchscreen circuitry but should give an idea of what is required.

With a Sharp SOC like that it was simple to add the touchscreen support on the board because of the integrated circuitry but with some additional components it should be possible to read the touchscreen using basic ADCs.
Often with XScale some additional peripheral IC with touchscreen controller is used. Like UCB1400 codec IC from Philips for example. Maybe there is some Gumstix add-on board with touchscreen controller ?
Author:  Ed_Ca22 [ Tue Aug 08, 2006 19:15 ]
Post subject: 
FYI, I have found loads of step up converters that would be perfectly suitable for this LCD - e.g. national LM2704 or Linear LT1944. The national chip is really nice and requires only a couple of components ;).

Ed.
Author:  new299 [ Thu Aug 17, 2006 17:22 ]
Post subject: 
Quote:
am looking to do exactly what you have done and have some questions; did you interface directly to the gumstix or using a controller? Could you give me details of the hardware/software implementation? Was it difficult to get Linux to work with the LCD? I will try to find a suitable step up converter - have you tried investigating how it was done on the Psion itself?

Did you get the digitizer working? Any ideas on how to interface to it? Is it just a pair of ADCs?


Hello, sorry, I only just saw your message. As far as software support, the gumstix linux has everything you need to drive the LCD, however the PXA255 framebuffer driver needs some work, it doesn't work in 4 or 8bit mode yet. So to get output to the Psion LCD I just set it to 16bit for the moment. Configuring linux to work with the LCD wasn't hard, just some settings passed to the kernel on boot if I remember correctly, though I don't have those settings to hand, I can try and dig them out. I believe I found the settings in the Series 5 Linux port source code at: https://sourceforge.net/mailarchive/mes ... id=1022474
which gave me: 81000 /* 12.346 MHz?, H: 19.290 kHz, V: 80.376 Hz */

The hardware setup on the gumstix is straight forward, you just connect up the LCD, the PXA255 has a builtin controller.

I've not done any work on this for sometime basically got hung up on the power problem (for my tests with the gumstix I took the power from the Psion motherboard). But I'd like to get it started up again, I've ordered samples of some of the national IC you mentioned. I'm not much of a hardware guy though.[/quote]
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