Labview control LCD by PC parallel port

[aludlak]

Thanks Dennis Knutson very much!

Before, I don't thinks we can use more I/O ports in a program. I'll do follow your idea, when it complete I'll say to you.

Members in there are fervour.Dear!

[Coq_Rouge]

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Dennis Knutson wrote:

Here's something quick and dirty. Since there are separate registers for the parallel port and you have wired the data register to the data inputs of the lcd and 2 of the control register pins for the E and RS, it made things a bit simpler.

I did not do anything about the instruction data to set the lcd into the mode you want. You can modify the data write VI and change the RS level to 0.

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Hi Dennis

Nice just as I would done I myself. But is not some of the bits in register address base+2 inverted by hardware in the port? This mean you have to write in "0" to get high output. See my compiled list. You should check this out aludlak. It is important 😉 

BASE ADDRESS + 2     (PCR) Control register (Read or Write)
Bit 0  Pin 1  DATA STROBE Output         Inverted
Bit 1  Pin 14 AUTO LINE FEED Output    inverted 
Bit 2  Pin 16 INITIALIZE PRINTER Output    
Bit 3  Pin 17 SELECT INPUT Output        inverted
Bit 4  0 = disable interrupt, 1 = enable interrupt    
Bit 5    
Bit 6    
Bit 7

[aludlak]

:Thanks Cop rouge!

I saw your compiled list. It really useful for me.

I still doing with this, I imagined the way have to do with it, but now it not yet complete. possibly my knowledge about Labview so limit.

Message Edited by aludlak on 04-25-2009 08:22 AM

[aludlak]

Hi, everyone!

I written initializing the LCD.But when I run it, I don't see any changeon my LCD. ah, while writting(chang the program) I saw 1 times the surcor on LCD but I don't know why, and now I can't see it again. Wold you please see again my test.

Message Edited by aludlak on 04-25-2009 09:57 PM

Message Edited by aludlak on 04-25-2009 10:01 PM

[Coq_Rouge]

I have made some small modifications. All 8 bit constants and controls do now have binary display. I have also left some work for you ;). You may run this VI standalone. I have set the default value for the data control to be the display on command.

Good luck

[aludlak]

Hic, my Labview v8.5 can't read your program labview 8.6.Now I have to downd v8.6 demo^^. Thaks you Cop rouge.

Message Edited by aludlak on 04-26-2009 03:43 AM

[Coq_Rouge]

Ok in 8.0

[aludlak]

I changed your subvi in to my program. but LCD still don't have any change. I conected E with 14 pin, it mean when E =0, RS=0 => bit 1 =1, bit 2 =0 (b10). don't understand it wrong where.

This Instruction I did follow your program Cop rouge. Would you please see again.

Message Edited by aludlak on 04-26-2009 04:31 AM

[Coq_Rouge · Accepted solution]

Your method is correct at least as I can see. Do get any error?. Also is pin 5 on the LCD connected to pin 1(gnd)? Have tried to insert some breakpoint so you can trace the data changing. I guess you have some sort of measuring equipment like a volt meter, or a scope

[Coq_Rouge]

also do your PC and LCD module share a common ground. You have to connect some of ground signals on the PC LPT port to the LCD ground