[SOLVED] PIC16F84A --> PIC16F819 FOR LCD.

[Shinnster]

Okay so I tried to use PIC16F819 to replace PIC16F84A,
but for some reason, PIC16F819 will not display Hello World.
Any particular reason?

Things to note:
I disabled MCLR, so I just left that pin as it is.
I use XT (4MHz) External so I config'ed that.
What other things I should take note?

 

[wp100]

Hi,

Worth checking all the config paramenters - but probably the commonest error is that if you are using Ports RA0 -RA4 for your lcd, your must select them for Digital I/O by means of ADCON1 as the chip defaults those ports to analogue at power on.

Does your lcd show a row of black blocks across the top row - that usually means the lcd is ok, but your progam is not running.

You could also try using the 4meg internal oscillator incase you have damaged or have a faulty xtal.

 

[Shinnster]

Oh, thanks for that.
Yeah the LCD was showing a row of black blocks.
I did try the 4Mhz internal oscillator. Wanted a similar circuit to F84A.

What is Write Enable for?

 

[wp100]

Hi,

What is Write Enable for?

? .. If you are meaning the E Enable pin of the lcd ? - have a look here
http://www.epemag.wimborne.co.uk/resources.htm

 

[Shinnster]

No, different, I'm talking about PIC16F819.
In the Configuration, WRT.
Nvm about it =]

 

[wp100]

Hi,

Not something I have used, but on your chip I think its turned on to allow the program to change its own program code while it is running !

See page 30 section 3.7 for details.

In a word, just let it use the default WRT config value as it not a function you will really want to use just yet.