12f675_fuse_about_to_blow!

[LEDave]

.....................

[LEDave]

Hi Henrik

Here's what I'd come up with late last night (I wish I'd posted it now before I went to bed as not the far off I don't think).

DEFINE LCD_DREG PORT.A        ' Set LCD Data port
DEFINE LCD_DBIT 0             ' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_RSREG PORT.A       ' Set LCD Register Select port
DEFINE LCD_RSBIT 4            ' Set LCD Register Select bit
DEFINE LCD_EREG PORTC         ' Set LCD Enable port
DEFINE LCD_EBIT 0             ' Set LCD Enable bit
DEFINE LCD_BITS 4             ' Set LCD bus size (4 or 8 bits)
DEFINE LCD_LINES 4            ' Set number of lines on LCD
DEFINE LCD_COMMANDUS 2000     ' Set command delay time in us
DEFINE LCD_DATAUS 50

I set LCD_LINES 4 as the display is a 4*20.

The one I'm missed was LCD_EBIT 0 (it was late).

Also the PIC is a 16F684 PORTA and PORTC

Thank you for taking the time to do go through it all though (really appreciated) I'll load it later today and hopefully have some success (I'm just a little worried I've fried the LCD).

David

[HenrikOlsson]

Hi Dave,
Ah, OK - I never crosschecked with the PIC datasheet, I only referenced your proposed connection scheme and LCD datasheet. So, PORTA and PORTC it is.

One thing though, there's not supposed to be dot in PORT.A it's just PORTA. The thing with DEFINEs is that they won't produce any error messages etc so you have to make sure you write them correctly or it simply won't work properly.

[mackrackit]

PORTA.3 is input only so you will need to move this over to portC.

[mackrackit]

How about doing it like this. The whole thing will be on PORTC. That will keep away from the MCLR and programming and POT(if still using the PICKIT1) pins.

DEFINE LCD_DREG     PORTC 'PORTC.0 WILL CONNECT TO DB4, PORTC3 TO DB7
DEFINE LCD_DBIT     0
DEFINE LCD_RSREG    PORTC
DEFINE LCD_RSBIT    4          'PORTC.4 CONNECT TO LCD PIN4
DEFINE LCD_EREG     PORTC
DEFINE LCD_EBIT     5            'PORTC.5 CONNECT TO LCD PIN6
DEFINE LCD_BITS     4
DEFINE LCD_LINES    4
DEFINE LCD_COMMANDUS 2000     
DEFINE LCD_DATAUS 50

LCD pins
1 and 5 to VSS
2 to VDD
3 to wiper on POT

[LEDave]

Hi mackrackit,

I've moved the whole thing over to the breadboard and wired it on there.

A couple of quick things:

Yes the manual shows a 10k res on MCLR, I've put one on PORTA.3 which probably isn't a good idea.

I've checked the voltage on the display itself earlier:

Across pin 1-2 = 4v (with pin 1 as GND)
Across pin 1-3 = it goes from 0 - 3.94v
Across pin 2-5 = 3.92v

Also (I've just noticed this) when I turn the POT, the top and third line of the display get darker, so something's going on or trying to.

[mackrackit]

I would turn MCLR off then you can use that pin as an input.

Display sounds like it is alive