Matrix user forums

This weekend was the 2012 National Hamfest at the Newark Showground (Nottinghamshire)
One of the bargins I picked up was a 2 x 20 Dot Matrix LCD display.
I was assured it was compatible with the Hitachi HD44780 display controller, i.e will work with flowcode.

I did notice the display has 18 physical connections, the second pin being labeled as pin 1
The first & last connections not being used.
A 16pin SIL header was soldered to the board and it was connected to the EB006 by means of a protoboard.

The usual "Hello World" program was loaded into the PIC, and the display burst into life.

The only minor problem is it does have quite a high current drain (260 mA) compared with a standard LCD e-block.
The 5V regulator on the EB006 was getting quite warm, so I think a seperate PSU will be needed to use it with the programmer.
The size can be judged by comparing it with the Matrix Protoboard

I have so far been unable to find any more data on the board.
It would be useful if the edge connector could be utilised.

Hi John,
I was just wondering how you are controlling contrast in the LCD..I can't see any POT in the picture. Is there any option to control the back-light of the LCD i.e., A and K of the back-light? In that case current requirement could be easily controlled..Bcz I have had a look in the user guide of the LCD it doesn't say that it requires so high current.
May be I am wrong but 260 mA is lot of current for just an LCD

Enamul,

It looks like a VFD (Vacuum Fluorescent Display), not an LCD, to me. The current is not out of the ball park for those displays.

Regards,

Jac

Hi
Ive not tried putting a pot on to control the brightness yet. I assume as it is compatible with the Hitachi controller, a pot will go across the normal pins.
I just wanted to try it and see if it powered up. Will try that later. Just nice to see it works.
As Jac points out it does look like a VFD.
The main chip on the back is a PT6314-001 which is a (confirms Jacs post) VFD driver.

Will have another dig on Google see if I can find any more data on it first.
There are 3 part numbers on the back.

VFM202MDA2-1

PC-0458-01-DS

F0503003

Ive just noticed the socket on the LHS is actually for test points.

I would not connect a pot before finding a data sheet. VFDs tend to have software brightness control, not hardware.

Thanks for that.

It does not really need brightness control anyway, so unless I can be sure what it will do I'll leave it as it is.
At least its working, apart from the high current needed I'm happy as it is.

here you go john have a look at this . . not sure if it yours or not

http://www.ec21.com/product-details/20- ... 65657.html

or

http://www.zboe.cn/ShowProducts_en.asp?id=80

There is some contact details on the pages

Steve

Found this data sheet hope it's of some use

Files are compressed with 7-Zip Please change .txt to .7z as the file ext as wasn't allowed to upload attachment

http://www.7-zip.org/

Steve

Thanks for the feedback
The data sheets seem to cover the display module itself, so I have some info to look at.

i have another data sheet for a 2 x 8 display which i am told is the same apart from the obvious change in lines

and have also been informed that the socket on the side connnects to the sil header so that you can use either

i can post it if you wish

steve

Hi Steve

Yes please, always usful to see alternate datasheets.
Looking at the tracks on the back of my board, I though the connector on the side was for test points.

Think what im going to do is mount it on a seperate board, with a 5V regulator. Then I can connect it to the 12V power on the programmer and draw power from the psu itself.
That way its not drawing power through the 5V reg on the EB006.

Here you go john,

got the info from techincal sales at midas they have some interesting stuff i could really upset my other half and my bank manager

a good idea to power it from a seperate regulator i use a big 5 volt power supply now so i don't have to worry about current draw too much

http://www.midascomponents.co.uk

Files are compressed with 7-Zip Please change .txt to .7z as the file ext as wasn't allowed to upload attachment

http://www.7-zip.org/

Thanks Steve
Looks like some interesting stuff on that site. Ive bookmarked it in my component suppliers section.

Thanks for posting the information. Especially about pin 2 being pin 1.
I thought I had bought a dud, but all looks OK.
(Sorry it's an Arduino!)