Difference between the cfag12864Btmiv & wghn#

C

CPIntern

New member
Hi, I wired up the cfag12864b-TMI-V and used the same test bench for the cfag12864b-WGH-N#. The WGH-N# didn't even turn on. I thought the same board and components were used for both LCD's. After comparing the boards, I noticed that the WGH-N# model does not have the U4, C1, C2, A10, JE, and Q1 components. Also, the cfag12864b-WGH-N# is not turning on with the typical Vo connections for the display contrast.

What are your suggestions for powering the display contrast for the cfag12864b-wgh-N? I did a continuity test and found out that the LCD turned on as soon as I tested for pins 3 and any combination of it with pins 4-16. Also, it turns on when I test pins 3 and any combination of 1 or 2.

Do you have a data sheet or schematic that shows what the missing components do?

I know you don't support connecting the LCD's to the parallel port, but how could I wire the cfag12864b-WGH-N# into the parallel port? Is it the same as the TMI-V wiring?

Thanks for your time.
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C

cosmicvoid

Master
The components missing on the WGH-N are for the negative voltage generator. It does not have negative voltage supply like the WGH-V does (and the TMI-V). Otherwise, the connections for the two displays are the same.

You will have to find a source of -5 volts in order to get optimum contrast with the WGH-N, or you could add the missing components to the board yourself, as others have done. https://forum.crystalfontz.com/showthread.php?t=5531
 
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C

CPIntern

New member
Thank you for the link cosmicvoid, it was very useful. We decided to work with the TMI-V instead since it already had the negative voltage generator and components. Now I will start working with the C++ code.

Thanks again.
 
C

CPIntern

New member
That's the source code I've been using :) . I ran it with visual studio and have been able to communicate only with the top part of the LCD. I suspect that there is a problem with the loose wiring I have on the breadboard. We've ordered a few headers, connectors + a traced board to connect directly to the parallel port.

This is the wiring I've been using: http://www.skippari.net/lcd/sekalaista/crystalfontz_cfag12864B-TMI-V.png

I'll keep looking at the responses on the cfag12864B-TMI-V. I've seen various helpful threads on the wiring and C++ code.

Thanks for your response.
 
C

cosmicvoid

Master
C

CPIntern

New member
The correct wiring for the WinTest

Hi, thanks for your previous help. The Cfag12864B-TMI-V is working fine with the parallel port, I was able to display the trailer, logo, H&V lines and checkers. I do have to add one correction though, it only worked by switching DB25 pin 14 to CS2, and DB25 pin 17 to CS1 on the WinTest C++ commented code provided. I would stress people to have the wiring right and check the parallel port. It is very easy to fry the LCD if your wiring is not right.
By the way, my problem was that the parallel port cable only had continuity in 17 out of 25 pinouts.

Thank you again for all your support.
 
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