Programming 16F628 while connected to LCD - Page 2 - Electronic Circuits Projects Diagrams Free

ericgibbs · 29th September 2007, 03:34 PM

Greg,

You say it programs OK when you physically disconnect PIC pin #10 from the LCD???

As a test keep pin#10 connected as normal, start the program sequence and measure what voltage level is actually on pin #10 throughout the sequence, voltmeter or scope would do it.

Lets know what voltage level you see on this pin.

blueroomelectronics · 29th September 2007, 03:35 PM

Without the comments and probably better labels it'll be tough going to decode someone elses source code, especially if you're not yet that familiar with the PIC. LCDs can be tricky until you get the hang of them, 4bit mode even more so.

The commands are (TRIS PORTx and OPTION)
they won't compile and have to be changed to movwf TRISx and movwf OPTION_REG

gregmcc · 29th September 2007, 04:31 PM

Eric - I've put a scope on pin 10 - its a constant 5V throughout the programming. I guess this is why it keeps failing. Dunno why I didnt think of doing this before! I've now put a 10k from pin 10 to ground and its working!!! Wooo hoo!!

Bill - I know its going to be tough, but I'm going through the code add tons of comments and proper labels - this way I can slowly step through the code finding out exactly what it does. I'm sure there's an easier way but I'll put it down to the learning process

Thanks for all the help!!

**Nigel Goodwin** · 29th September 2007, 05:01 PM

You might try using WinPicprog to disassemble it, as it adds labels for you - you still have to edit them to make sense, but at least it's one job less!.

Having said that, I've done it for you!.

gregmcc · 29th September 2007, 06:41 PM

Thanks! Should make things a lot easier.

pasanlaksiri · 30th September 2007, 09:33 AM

Quote:

Originally Posted by gregmcc

I've build a LCD clock using the schematic attached. The first time I program it using a Inchworm everything programs fine. If I recompile (mplab) and want to reprogram the PIC I keep getting errors. (verification failures)

I've done some fiddling and its to do with the PGM pin being connected to the LCD - if I disconnect the LCD it programs fine.

While this solution is ok I would like to program without disconnecting the pin all the time. I've tried a 10k resistor between the PIC pin10 and the LCD but no luck.

Whats the trick here to get it working?

Hey few months ago, i maked this and it worked nicely.

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29th September 2007, 03:34 PM	(permalink)
ericgibbs	Greg, You say it programs OK when you physically disconnect PIC pin #10 from the LCD??? As a test keep pin#10 connected as normal, start the program sequence and measure what voltage level is actually on pin #10 throughout the sequence, voltmeter or scope would do it. Lets know what voltage level you see on this pin. __________________ Eric "Good enough is Perfect" PIC tutorials: Gramo's: www.digital-diy.net/ Bill's: www.blueroomelectronics.com/

29th September 2007, 03:35 PM	(permalink)
blueroomelectronics	Without the comments and probably better labels it'll be tough going to decode someone elses source code, especially if you're not yet that familiar with the PIC. LCDs can be tricky until you get the hang of them, 4bit mode even more so. The commands are (TRIS PORTx and OPTION) they won't compile and have to be changed to movwf TRISx and movwf OPTION_REG __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com

29th September 2007, 04:31 PM	(permalink)
gregmcc	Eric - I've put a scope on pin 10 - its a constant 5V throughout the programming. I guess this is why it keeps failing. Dunno why I didnt think of doing this before! I've now put a 10k from pin 10 to ground and its working!!! Wooo hoo!! Bill - I know its going to be tough, but I'm going through the code add tons of comments and proper labels - this way I can slowly step through the code finding out exactly what it does. I'm sure there's an easier way but I'll put it down to the learning process Thanks for all the help!!

29th September 2007, 06:41 PM	(permalink)
gregmcc	Thanks! Should make things a lot easier.