LCD setup

[ruijc]

Hi guys,

i'm changing my lcd wires from the stardard configuration but i'm not getting this to work ( maybe it's too late and cant think right ) !!!

The idea is to:
lcd RS to pic RA4
lcd E to pic RB4
lcd DB to pic RB0,RB1,RB2,RB3

i'm using these defines:

Define LCD_DREG PORTB
Define LCD_DBIT 0
Define LCD_RSREG PORTA
Define LCD_RSBIT 4
Define LCD_EREG PORTB
Define LCD_EBIT 4

thanks

[nomad]

you show RS on pin ra4 but define says rsbit 3. also typically ra4 is open collector or open drain as an output and will need a pullup resistor. which pic are you using?

[nomad]

hey no fair you changed it while i was posting. lol. ok so that leaves the pullup issue.

[ruijc]

hehehe...

sorry nomad,

right now i'm slow thinking, but i got there

i'm using a 16F628.
Also have a pullup 100K resistor...but still not working...

.

[nomad]

100k might be to large. too weak a pullup. i usually see 10k or even 4.7k as the pullup. check your input/output trisA settings and disable comparators, cmcon=7? ra4 is tied to cmp2.

[nomad]

oh yeah, also make sure the R/W line isn't left floating. needs to be grounded i believe. did you set 4 bit mode? DEFINE LCD_BITS 4. thats all i can think of without having the data sheet here or seeing the code. hope that helps.