LCD and 16F88

[savnik]

Low PORTA.4 ' LCD R/W line low (W)
Pause 1000 ' Wait for LCD to start

Delete the first line and add a pullup ressistor to RA4

[sayzer]

What about the contrast POT of the LCD?

May be it is working but because it is too dark, you see nothing but blocks!

Trim the POT until you see something on LCD.

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[mister_e]

or the LCD R/W pin is left floating or set to high. In your first code example you said

Low PORTA.4 ' LCD R/W line low (W)

As A.4 is actually the LCD RS bit, it can't work.. or i miss something?

BTW, i've tested it here, with your current setting, and it's working.

        DEFINE LOADER_USED 1

        Define LCD_DREG PORTA
        Define LCD_DBIT 0
        Define LCD_RSREG PORTA
        Define LCD_RSBIT 4
        Define LCD_EREG PORTB
        Define LCD_EBIT 3
        Define LCD_BITS 4
        Define LCD_LINES 2
        Define LCD_COMMANDUS 2000
        DEFINE LCD_DATAUS 50
        
        CMCON = 7       ' disable analog comparator
        ANSEL = 0       ' disable ADCs
        Pause 500       ' LCD start up delay

        Lcdout $fe, 1, "LCD Test"

Here:   goto here       ' spin here forever

[G-R-C]

Hi All
I'm happy to say my LCD is up and running. I'm impressed by the number of
quick responses to my question.

Thanks to all for the replies and tips. You guys are great.
Gordon

[mister_e]

You're welcome!

You guys are great.

Yeah we know

Just to satisfy my own curiosity... what was the problem???

[G-R-C]

The problem was a couple of issues. The port wasn't set to digtal (ANSEL),
Another was the pull-up resistor was omitted. I checked the data sheet
to make sure the CMCON was turned off, but somehow didn't realize the
ANSEL register needed to be set to 0. Bet I wont forget about this register
in the furture.

Thanks again all.
Gordon

[mister_e]

Just to set the record. For this device and by the datasheet, PORTA.4 is not an open drain as some suggested. It's really a full CMOS output pin. So you don't even need the pull-up resistor.

But YES, you have to disable the internal analog comparators and ADCs.

Bet I wont forget about this register

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