12f675_fuse_about_to_blow!

[LEDave]

Getting an LCD up and running might be a good experiment, and it's also a handy tool for debugging code later.

I'm game, don't forget I couldn't turn an LED on a few weeks ago though!

Dave

[mackrackit]

Is there a surplus store over there like this?
http://www.allelectronics.com/make-a...splays-/1.html

[LEDave]

There's RS

They have these (and I've got an account).

http://uk.rs-online.com/web/search/s...20Alphanumeric

Or Maplins again:

http://www.maplin.co.uk/Search.aspx?...=lcd&source=15

The RS range seems far superior.

Dave

[Byte_Butcher]

I'm game, don't forget I couldn't turn an LED on a few weeks ago though!

Sure, most of us couldn't flash an LED when we started.
But Mackrackit is doing a nice job of getting you up to speed, and a parallel LCD display isn't that hard to set up.

You'll need to set up 4 pins on your PIC, all on one port for your LCD data lines, and 2 more pins for Enable and Register Select
You'll need to make sure that those 6 pins are setup as digital outputs and any other stuff that shares those pins (ADC, comparators, etc) are disabled.
Once the pins are set correctly then you'll add a few DEFINE's to your program to tell the PIC where to find your LCD and what pins are what.
Like this, but with YOUR particular ports and pin numbers that you are using:

DEFINE LCD_DREG PORTD    'Set LCD Data port
DEFINE LCD_DBIT 4        'Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_RSREG PORTE   'Set LCD Register Select port
DEFINE LCD_RSBIT 0       'Set LCD Register Select bit
DEFINE LCD_EREG PORTE    'Set LCD Enable port
DEFINE LCD_EBIT 2        'Set LCD Enable bit
DEFINE LCD_BITS 4        'Set LCD bus size (4 or 8 bits)

Then it's just a matter of using the LCDOUT command...

LCDOUT $fe, 2, "HELLO WORLD"

or if you wanted to display the content of a variable as a decimal number:

myvariable		var		word
myvariable = 3955

LCDUT $fe, 2, DEC myvariable

It's easy!


steve

[mackrackit]

Has anyone used this one? Is it any good?
http://uk.rs-online.com/web/search/s...duct&R=5326795

[LEDave]

Hi B_B

Ok, I'm sold

These LCD's look like great fun and a really useful interface.

When my first LED came on, that was brilliant. When my seven segment display /
driver lit up and counted up to nine that was cool.

These look in a different league, can't wait.

Dave

[Byte_Butcher]

Has anyone used this one? Is it any good?
http://uk.rs-online.com/web/search/s...duct&R=5326795

That one doesn't look like it's got a backlight. One with a backlight would be sexier...

Here in the US, I find these to be a good deal for $10USD.
http://search.digikey.com/scripts/Dk...ywords=c0220az
Don't know about UK vendors.


steve

[mackrackit]

Interrupt on change (interrupt when the state of a pin changes)
Again this is a snippet from another chip (16F873A) but it will give you something to start with.

ON INTERRUPT GOTO MYINT
INTCON = %10010000   'PORTB.0 CHANGE

DISABLE
MYINT:
IF PORTB.0 = 1 THEN
    ' DO SOMETHING
ELSE
    'DO SOMETHING ELSE
ENDIF
INTCON.1 = 0
RESUME
ENABLE
 'THE ABOVE WILL ALSO DEBOUNCE THE SWITCH

[LEDave]

Cheers mackrackit,

I made a little table up that other newbies who are maybe following this thread might find useful. It hinges on what you said the other day about setting the prescaler (TMR0) and using that with (I = I +1) to set up a delay of your choosing.

BIT TMR0 Time_u_secs HZ
000 1:2 512 976
001 1:4 1024 488
010 1:8 2048 244
011 1:16 4096 122
100 1:32 8192 61
101 1:64 16384 30.5
110 1:128 32768 15.2
111 1:256 65536 7.6

Didn't quite come out as planned and every time I edit it the changes I make it just resets.
Still, I'm sure you get the drift (might be worth checking my figures as well though).


Any thoughts on that LCD?

Dave

[LEDave]

I've just had a thought.

It's probably dangerous for me to offer advice right now, no matter how well intensioned. As some of my conclusions maybe a little off the mark.

Dave