GLCD

[David HK]

Hello,
I'm new to the board and have been reading it for more than 5 years. I'm British, retired Hong Kong police and still live in HK. I am aged 61 and may find software writing a challenge. I therefore hope that the experienced members of this very friendly and helpful board can bear with me.

I have built my own renewable energy system which is a mix of sun tracking PV array, wind turbine, system distribution, storage, dump load et al. It is 12 volts, but given the money I would upgrade to 24 or even 48 volts. The more volts you have the easier it is to play with the electricity.

After ransacking my local scrap yard I now have 2 Densitron GLCD's. Densitron LWM240128B-A-DNY. I also have the data sheet which is difficult to find even with Google.

I would like to set up the GLCD's to display Volts and Amps coming from the PV array - that's all - just visual monitoring. I can design PCB's from circuits and am au fait with the care needed for clean PIC power supplies.

To start with I need two forms of help - the first is to ascertain what Picaxe would suit, and secondly can you tell me what info you need from me so that I don't waste your time and mine.

I have searched the board for GLCD's and looked at other projects - some are close,but I cannot find any the same. Please advise if you know of anything very close to what i propose.

If I can get this running it will be worth more than Cleopatra's dowry!

Dave

 

[Andrew Cowan]

Can you post the datasheet for your GLCD? Do you know what driver chip it uses? What size is it?

Welcome to the forum!

A

 

[David HK]

Andrew,

I hope I am not giving you work, but if you go to the Densitron URL:-

http://www.densitron.com/displays/Search.aspx?partnumber=LM6729&search_type=1&cat_id=0

and then type in LM 6729 you will be able to access the entire PDF.

Hope this helps.

Dave

 

[Andrew Cowan]

Hi Dave

I can see it is a 128x240 LCD, but it says Registration Form - Please Register to Download Datasheet.

Can you upload the datasheet to this forum? (Go Advanced Reply, then Manage Attachements (scroll down).

A

 

[westaust55]

An alternate way to add an attachment when you have opened a post window for the first time is to just click on the paper clip icon (next to the smiles icon) immediately above the text window.

 

[David HK]

This is a new experience. I think I have attached the PDF.

Dave

 

[westaust55]

About to head out the door here but looking at the datasheet a few hardware issues to resolve first.

1. Need to identify exactly what LCD control you have onboard.
If it has an onboard negative voltage generator, then life will be slightly easier.

2. Which PICAXE chip are you proposing top use?
The interface uses an 8-bit parallel data bus bit like an older (centronics style) printer interface plus 3 or 4 extra signals.


Would recommend one of the X/X1 series.
Then you could use an MCP23017 with two 8-bit ports. One to present the 8-bit data to the LCD and either 3 or 4 lines direct form the PICAXE or via the second port. If you have the controls direct form the PICAXE then you can always use the other 8-bit port on the MCP23017 for other inputs or outputs.

3. The backlight is the CCFL type. If these are salvage, did you get the High Voltage generator board for the backlight as well? These step up from around 12V to 100 (or more) volts


Software:
You are going to need to download and digest the LCD controller datsheet. Available:
http://materias.fi.uba.ar/6609/docs/SED1330.pdf

 

[David HK]

The controller on the PCB is a Toshiba 6963C and there is no sign of SED 1330.

I have sent an e-mail to Densitron USA asking them to confirm that the Densitron No LWM240128B-A-DNY corresponds to LM 6729. The initial e-mail reply was Why do you wanna know! I sent back a pleading reply.

After studying the PDF data sheet many of the characteristics match with the raal device.

The PCB does contain white lettering - 94V-0. What that is indicative of I am not certain. There is also a LA6324N IC on the board. The connector pins total 1 to 20. Apart from that there is little else to go on.

David

 

[David HK]

After more research I think the reference to LM6279 is wrong because that PDF shows a SED 1330 controller.

The PDF for the LM6229 shows the Toshiba T6963C controller which matches what is on the PCB.

 

[lbenson]

Unless you are looking for a challenge, and perhaps a considerable one, if all you want to display is volts and amps (numerically, not graphically), it might be much quicker to use something like the Sure Electronics 20-character by 2 lines lcd module for $4.99US, shipped:

http://cgi.ebay.com/2002-LCD-Module-black-character-no-backlight_W0QQitemZ350284238550QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item518e914ed6

This can be driven by a PICAXE14M with Hippy's code, as shown here: http://www.picaxeforum.co.uk/showthread.php?t=9662 That thread includes a picture of the Sure module powered by Hippy's code.

For more processing power and more i/o at little more expense, I'd recommend the PICAXE20X2.

 

[David HK]

Ibenson, you're right!

Folks I give up and will follow good advice.

Now what to do with the GLCD's?

David

 

[lbenson]

>Now what to do with the GLCD's?

Sometimes the best thing to do with recalcitrant or poorly documented gear is to bin it, even if you think you're close to getting it to work. If I had followed that advice for any number of items, I'd have saved myself days--but actually they tend to go to the back of a drawer in usually idle hope that someday I'll find time, inclination, advice, or documentation to make it work.

Even putting it in the back of a drawer is hard for me, which is part of the reason my desk is an utter mess.

 

[boriz]

"Even putting it in the back of a drawer is hard for me, which is part of the reason my desk is an utter mess."

LOL. Me too.

 

[Dippy]

David, you will struggle driving a GLCD directly from PICAXE.
The T6963 should be a little easier as they have a character set on-board and have separate text & graphics layers - nice for a DIY 'scope display. Many others, including the cheaper/popular KS0108, require external fonts. There are advanatges to this.

I haven't looked at that Data Sheet, but normally you need a big data sheet showing the logic/timing diagrams to know which bits to set high to define shoving in commands or data.
To get any decent drawing/refresh speed you will have a hard task.

I've written drivers for the T6963 on another processor and even that wouldn't be fast enough for slick animation.

If I were you I'd see if I could get hold of a GLCD driver or use the Rev-Ed's GLIC+KS0108GLCD or similar or just use a character LCD.

Sadly, some of these places give the impression that driving GLCDs are as easy as plugging the aerial into your Telly - it ain't.

 

[westaust55]

gLCD vs chracter LCD modules

I've written drivers for the T6963 on another processor and even that wouldn't be fast enough for slick animation.

Sadly, some of these places give the impression that driving GLCDs are as easy as plugging the aerial into your Telly - it ain't.

Having in the past done some work with a 102 x 64 gLCD from a Siemens A55 mobile phone that has a serial interface, it takes from memory around 2 seconds to refresh the entire screen. a Few lines of text alone would be faster.


If you go the way of a more conventional 2x16 or 2 x 20 LCD display module
I have built an interface using 2 or 3 signals:
http://www.picaxeforum.co.uk/showthread.php?t=13900
But while I had no problems, suggestion are that timing on some displays could be more crucial than those I used and such a scheme may not always work.

Another option to achieve a serial interface and thus reduced the PICAXE pin count is the Rev Ed FRM010 serial to parallel interface chip.
http://www.rev-ed.co.uk/docs/frm010.pdf

 

[Dippy]

I think the best I ever got was about 0.2 seconds for a graphics image write on a KS0108 128x64, so not good enough for animation. It was possible to upddate smaller areas of the display a lot faster though.