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View Full Version : Optrex DMC20434 20x4 LCD Panel



jeffjohnvol
04-18-2007, 08:56 PM
I bought a kit many years ago when I was considering getting into working with BX-24 chips.и I never did the development, but I still have this LCD panel.и It comes with instructions to use with a BX-24.

Has anyone here interfaced one of these with a stamp?и The instructions come with a 74hc595 serial shift register, so I assume that I would need to use it if I didn't want to use all of my outputs.

Picture of one:
http://cgi.ebay.com/Optrex-DMC20434-4x20-character-LCD-like-new-parallel-IF_W0QQitemZ110095854347QQihZ001QQcategoryZ26206QQ cmdZViewItem

Specs
http://www.zap.org.au/elec2041-cdrom/board/doc/data/optrex-20x4-lcd-module.pdf

I've searched this forum for this and googled, but couldn't find anything related to a stamp solution.

Loopy Byteloose
04-18-2007, 09:59 PM
Hi Jeff,
If the LCD panel fits the defacto Hitachi standard for intialization, it is quite easy to use with a BasicStamp because the code has already been written and the Nuts & Volts articles have very clear explanitions.

In another thread, you mention using the BS2. That is actually a 2nd choice for LCDs and the more advance stamps both have more room for code and PBasic supports LCD functions without having to write out every bitty thing.

My own experience with buying other LCDs [not from Parallax] has been mixed. I bought a couple locally in Taiwan that have the same Hitachi intialization, but to my surprise I destroyed the first one because the Vdd and Vss were reversed.

In sum, if you can get the original documentas and compare ALL the details - you will have a better outcome. LCDs last for about 2 seconds at reversed polarity. It doesn't matter if it is the correct voltage and well regulated.

The 74hc595 serial shift register may have been provided to to reduce the Parallel Interface [which requires about 11 pins in full parallel] to a simple SHIFT IN interface. If you can use the 4bit input mode rather than the 8bit input mode, I would not bother with the shift register.

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"If you want more fiber, eat the package.и Not enough?и Eat the manual."ииииииии


ииииииииииииииииииии Tropical regards,иииии G. Herzog [и黃鶴 ]иin Taiwan

Loopy Byteloose
04-18-2007, 10:04 PM
Hi again,
It looks like the Hitachi standard is used [refers to HD44780 or equivalent in the documents]. It has 4 bit mode. Just make sure that you don't get your power lines reversed.

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"If you want more fiber, eat the package.и Not enough?и Eat the manual."ииииииии


ииииииииииииииииииии Tropical regards,иииии G. Herzog [и黃鶴 ]иin Taiwan

jeffjohnvol
04-18-2007, 10:44 PM
Kramer said...
Hi Jeff,
If the LCD panel fits the defacto Hitachi standard for intialization, it is quite easy to use with a BasicStamp because the code has already been written and the Nuts & Volts articles have very clear explanitions.

In another thread, you mention using the BS2. That is actually a 2nd choice for LCDs and the more advance stamps both have more room for code and PBasic supports LCD functions without having to write out every bitty thing.



Thanks.и Yeah, I was thinking now about the BS2px.и Its only $30 more and seems to have some LCD commands.и It draws more power, but that shouldn't be a concern since it won't be running off of a battery.

I have this one for free, if it toasts (hopefully not), no real loss, I'll just get another solution from Parallax that's tried and true.

Chris Savage
04-20-2007, 01:24 AM
Jeff,

Code and wiring examples for Hitachi compatible LCD Displays can be found on our website at the following link. Take care.

http://www.parallax.com/detail.asp?product_id=603-00006

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Chris Savage
Parallax Tech Support

prousselot
09-17-2013, 08:37 PM
Jeff,

Code and wiring examples for Hitachi compatible LCD Displays can be found on our website at the following link. Take care.

http://www.parallax.com/detail.asp?product_id=603-00006

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Chris Savage
Parallax Tech Support

Hi Chris,

I dug this thread from the past as I have the same lcd display. The link gave is not anymore valid. would you have by any chance a new link ?

here is a link for the picture of the lcd http://lonvic.web.fc2.com/WorkShop/Optex_LCD/menu.html

Thanks in advance

Philippe