Newhaven 4x40 LCD, issues!

[mackrackit]

http://www.picbasic.co.uk/forum/show...ght=lcd+anypin

[Christopher4187]

http://www.picbasic.co.uk/forum/show...ght=lcd+anypin

Thanks for the link. Regarding my other question, is there any great benefits to using 8 bit (clarity/speed) or will 4 bit do the job? If 4 bit will do the job, just so I understand correctly, I need 7 pins from the PIC:

1. RS
2. R/W
3. E
4. Low order, bi-directional (1)
5. Low order, bi-directional (2)
6. Low order, bi-directional (3)
7. Low order, bi-directional (4)


Am I on the right track?

[mackrackit]

R/W goes to VSS.

8 bit is a tad faster by the math but I do not think it is humanly noticeable. I never use 8 bit as pins get ...expensive...

[Christopher4187]

Are you sure the R/W pin goes to ground? DT's program and the datasheet both show that R/W gets connected to the PIC. I ask because I'm not getting anything on the screen. DT's programs seems to have complied just fine, although I'm not sure if I did everything correctly.

[mackrackit]

Not sure where you saw Darrel connecting RW to the PIC, in fact he says not to in this post.
http://www.picbasic.co.uk/forum/show...=2388#post2388

The R/W pin is exactly what it says Read/Write, with 0 being Write.

Do you have the contrast pin connected to a pot as recommended? That is the most common problem. That should be pin #3 on the display. Not sure why the data sheet does not so it. Got to have contrast control.

[Christopher4187]

Sorry, it wasn't Darrell. It was NavMicroSystems in this picture. Anyhow, I literally get nothing. I can't even see the screen flicker. I've verified it has 4.8V at the power input and I've tried using a pot to adjust the contrast. I've only used serial LCD's from SEETRON in the past so this is new to me. Is there a basic way to test the screen? Like applying power to the LCD and +5 to another pin will display something?

[mackrackit]

I do not know of a test.
Post your code and connections/schematic.
Maybe we will be able to see the problem.