LCD Display not working - PIC heating...

[flotulopex]

Hi BobK,

I have the same kind of approach as you have. When nothing works = restart from scratch step by step.

Now, to your suggestions, here are my answers:
- Yes, I can easely program all my PICs without any trouble. That's the reason why I built different programmers before I really started programming.

- Yes, I have checked my PICs ( I have 16F84A, 16F88 and 12F675 - actually I'm working with the 16F88) almost as you suggest and everything is fine; the PICs are all okay.

- My code is is the 1st post of this thread and I corrected it according to your informations (DEFINES).

- Mister_e is right; the breadboard my be a source of contact problems and this is why I have made test on my second breadboard too (the BasicStamp Pro Developpement Board).

- Yes, I disconnect MCLR, DATA and CLOCK wires after programming the PIC (see a previous post).

- I use the internal oscillator on pic 16F88 (no external crystal or resonator).

- The fuses look to be set correctly; LPV is disabled.

- In my code, I have made a 1 second pause to let the PIC and the LCD stabilise (may not be mandatory but I thought it would be better so).

Mister_e, your schematic is great. Is your "Program/Run" switch automated (kind of monitoring the signal on MCLR)?

I'm still in the office now and should have a new display waiting for me in my mailbox. I'll give you an update asap. Please wait until I have connected my knew display... I'm confused to see you working on lots of possibilities and me not able to provide reliable informations.

[mister_e]

Mister_e, your schematic is great. Is your "Program/Run" switch automated (kind of monitoring the signal on MCLR)?

Hehe funny that you talk about that. Few days ago, i did an automated version to do the switching with a VB application. When the focus is set to the device programer software, the ICSP interface switch to the Program mode, when i close or return to the code editor it goes to the Run Mode. it's on testing.. pretty good as now

[flotulopex]

Finally

!!! IT WORKS !!!

I got my new display and connected it to my 16F88. Nothing :-(

I changed to my 16F84A and now it is okay.

I will try again with the 16F88 but I will use other ports than ports A.

I'll come back asap.

[flotulopex]

Mister_e,

You were right: LPV must be switched off to make it work.

As specified in the 16F88 data-sheet (chap 15-18), if LVP is selected, RB3 ceases to be a general purpose I/O pin. As I used this port in both tries (PortA and PortB), it coudln't work.

In a few words, here is what happened to me:
a.- three LCD displays not HD44780 compatible (even Murphy wouldn't have so much bad luck);
b.- LVP switched on by default in ICPROG (my programming software).

Thank you all for your support ...and patience.

Hope this thread will help other people too.

[mister_e]

Hé Flotulopex! on se fait une petite danse
<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=881&d=1148640458">

[flotulopex]

On thing is still unclear to me after this experience: the DEFINE commands.

Since I want to understand this thing clearly, I have wired my display once more on the "original" layout (as in post #1) and modified the DEFINE commands back to "original" too. No worries, still working.

I had to try this without the DEFINE commands and guess what, it works!!!

Since I understood these command would be almost mandatory, it's beginning again to be a mess in my (small) brain. I'll open a new thread with this question.

Thanks again to all of you.

***************************
Mille mercis Steve,

Tu avais la solution. Bravo! Alors, dansons la gigue :-)

[shahidali55]

Usually when a pic heats, it means it is fried. Try replacing it.
If the LCD also heated when the pic did, it could also be fried...

[ErnieM]

Since I understood these command would be almost mandatory, it's beginning again to be a mess in my (small) brain.

"Almost" is the opperational word here. The DEFINEs are optional if you connect the LCD the way PBP assumes you will connect them: data lines DB4-DB7 to Port A.0 to A.3, RS to A.4, E to B.3.

If you connected your LCD this way then the defines are truly optional (and since you said your code did work without them then you had to have done just that).

The manual says just this, check page 95.