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CFAH2004KTMIJP - Lines switched?

rocketPack

New member
I have an odd problem... My LCD is hooked up, powered on, and running well... sort of.

When I use a program, such as the CFAH* test program from CF, or any other program for that matter, I can spit out text like "LINE 1", "LINE 2", etc. for all 4 lines, and there is no problem. However, when I try to use dynamic content (having the lines update frequently, like 150ms but it still happens even if the refresh is 1s) I see the lines randomly switching, 1->3 and 2->4, and vise versa. I wrote a quick program in C++ and I noticed that if I just let the cursor advance itself while I print characters to it endlessly, it will go Line 1, Line 3, Line 2, Line 4.

Why is this? It seems like there is some kind of timing issue with the two controllers? Would this be fixed by running in 4-bit vs. 8-bit? It seems almost like a bug. I know you don't support these screens for my application but if you have any idea I'd appreciate whatever you have to offer - or if anyone else has encountered this and can help me troubleshoot the problem. Thanks,

-Scott
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rocketPack

New member
I just tried writing another program to check the addressing by switching the cursor to random places all over the screen, and it came out just fine. However, if I place the cursor at the last place on a line (eg: 1,20) and advance the cursor one position to the right, it moves 2 lines down (1,20 -> 3,1). I'm not sure if this is the problem that the 3rd party software is encountering, but it certainly seems odd to me that the cursor would move in such a way? Is this a wiring issue? Is my screen defective?
 
Originally posted by rocketPack ... However, if I place the cursor at the last place on a line (eg: 1,20) and advance the cursor one position to the right, it moves 2 lines down (1,20 -> 3,1).
That seems correct, according to the data sheet.
 

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rocketPack

New member
hum, you're right... so why can't the programs I'm using keep the text on the correct line? It doesn't make any sense for it to jump all over... I've tried LCDSmartie, LCDCenter, and one other one with no luck... It's very frustrating.
 
Maybe the 3rd party apps are not handling the overflow from line 1->3, or 2->4 correctly. I've only ever used my own code to drive these things, so I can't offer any experience on other drivers. You say it works fine with random cursor placement, so I'd always use explicit cursor placement instead of allowing line overflow.
 
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