204A LCD Problem, need help

[kenji]

Hello guys im a newbie on PICC and PIC. I'm working on a project that will display text on a 204A LCD. I'm using PIC16f877a microcontroller and Hi-tech compiler. The design is to make use of PORTA RA0:RA2 as controller for the LCD (RS,RW,E respectively), using PORTB RB4:RB7 as 4bit data interface.

I already set 0x06 to ADCON1 as this is what it takes to make PORTA digital output but still it didn't work. Did I missed something aside from the ADCON1 setting? Thank you so much.

 

[Jay.slovak]

Did you setup TRISA register to OUTPUT? Each bit in TRISA registers defines direction of PORTA, if you clear the TRISA,7 bit, it will set PORTA,7 to OUTPUT...

 

[kenji]

Thanks for the reply Jay, I setup TRISA to 0, presumably to set PORTA to output. I got this code running when using PORTB RB0:2 as LCD controls and PORTC RC4:7 as data. Seems it won't work using PORTA RA0:2 as LCD control and PORTB RB4:7.

 

[Jay.slovak]

It should work, try this

EXAMPLE 4-1: INITIALIZING PORTA

BCF STATUS, RP0 ;
BCF STATUS, RP1 ; Bank0
CLRF PORTA ; Initialize PORTA by
; clearing output
; data latches
BSF STATUS, RP0 ; Select Bank 1
MOVLW 0x06 ; Configure all pins
MOVWF ADCON1 ; as digital inputs
MOVLW 0xCF ; Value used to
; initialize data
; direction
MOVWF TRISA ; Set RA<3:0> as inputs
; RA<5:4> as outputs
; TRISA<7:6>are always
; read as '0'.

 

[GRC]

Hello All
Will the code above set PortA to digital. Seems like I read some
where that this port needed to be set for digital I/O, else it defaults
to analog.

Just a thought
Gordon

 

[GRC]

Oops, never mind, I forgot the ADCON1 sets the digital/analog.
Sorry for any inconvience.

Gordon