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CU40026SCPB-T20A-05 & Parallel mode... help a n00b
http://forum.lcdinfo.com/viewtopic.php?f=6&t=848		 Page 1 of 1
Author:  xSmurf [ Sun Sep 26, 2004 21:17 ]
Post subject:  CU40026SCPB-T20A-05 & Parallel mode... help a n00b
I've recently purchased a Noritake CU40026SCPB-T20A-05 VFD Display, my first display :), and need a few info. I've tried the display in Serial mode and it works perfectly. But I'd like to use it on the parallel interface. The reason for that is that I have built a simple Serial to Parallel interface which has 8 output and 8 input ports that will be used to control the music. For some reason I get nothing displayed when using the parallel mode. I'm guessing the display needs to be switched to the proper mode for it to work. Anyone has some info about this? There's nothing mentioned in the doc. I'm also unsure of the proper wiring for the (NOT)CS and (NOT)WR pins... will this affect the data transmission?

P.S. The interface circuit I'm using can be found at http://www.jbgizmo.com/page2.html, pin out for the 6402 UART can be found here
Author:  Henri [ Mon Sep 27, 2004 9:49 ]
Post subject: 
I have only experience with the CU20045SCPB-T23A model but I think these should have the same interface. I don't remember there being anything to switch from serial to parallel mode. It will detect the used interface itself I think. There were some solder jumpers for serial settings but those should be of no use as you already have serial working.

/CS has to be at low level for the display to accept any commands. You could just ground it for example if you want to save interface pins. Then /WR is the signal that tells the display to read the data byte from the D0-D7 lines so it's very important.

It goes something like this:
Set /CS low, /WR is high.
First you put the databyte to the D0-D7 lines and then set /WR low. This should make the display read the byte from D0-D7 lines. Then set /WR back high and you can also set /CS high.
You should confirm the correct sequence and timing from the timing diagrams in the datasheets.
Author:  xSmurf [ Mon Sep 27, 2004 16:59 ]
Post subject: 
Hmmm I think I get it... The chip has these two pins which I believe are the ones I'm looking for :
Quote:
Pin 18 / nDRR / Data Received Reset / Active Low. When low, sets Data received Output Low (i.e. Clears DR)
Pin 19 / DR / Data Received / When High, Data has been received and placed on outputs RBR8:RBR1.

So I place an NOT gate on the DR connected to nDRR, so when it's activated it will get reseted. And another NOT gate from DR to CS. and plug WR directly to DR. What do you think... should this work?
Author:  xSmurf [ Tue Sep 28, 2004 16:54 ]
Post subject: 
Yup it works great, I grounded CS low at all time and used a Hex Inverter (NOT gate) to reset the DR (to which WR is wired) as soon as it comes high... Driving the whole thing at 57600bauds. Thanx for the info. Hope this helps others!
Author:  bprijs [ Sun Dec 07, 2008 15:46 ]
Post subject: 
Hello it's bin a while that anybody have written the last thread here but i have also a problem with this display.
I hooked it up on my parallel port and it gives only one line in one block.
This is the line that normaly goes from left to right.
Sometimes it goes a few blocks further but thats the only thing that happens.
But when i close lcdinfo then the display tells (goodbye!).
So i think it's a configuration issue so i hope someone can help.
As i can reed here above you must set Cr Low en WS High but the only things i can set are: strobe, line, init and select.
Also there are more things like: Port 0x278 or 0x378, Delay, presets and brightness.
Can anybody tell me what to do.
Sorry for my bad english.

Kind regards Branko
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