migration from 16F876a to 18F25k22

[Demon]

I have 100R and 1K pots on my circuit; backlight and contrast (can't say which has which pot by looking at it).


Look at the Electronic Parameters at bottom left:
Voltage Logic 5V typ.
Voltage LCD 20V typ.

The LCD has a range of 4.5 to 30 volts, 5 volts should work, and I'd stay away from the upper max. I'd start with an old PC power supply (5V and 12V) and give that a shot if you don't have a variable power supply, or a bunch of old wall adapters.

So yeah, I'd go with 500R pot on LEDA and 10K pot on V0 to start, and then tweak until I hit a pot that has an acceptable range. You'll see a sweet spot when you get to the right one; from dark to not "too" bright. Brighter LEDs mean shorter life, I aim for the just-enough-for-me range.


I also noticed something else on your datasheet; CONTROLLER: RA8835 OR EQUAL. I'd do some googling on RA8835 and see if more examples come up. You can never have too many schematics, tables or descriptions.

Robert

[MOUNTAIN747]

Thanks Robert, I'll let you know how it turns out!

[Demon]

I used the 16F628 and 16F877 before but it looks like I'll have to move up the food chain and the 18F2xK22 and 18F4xK22 series look like just what I need. At least I'm not forced to upgrade to PBP 3.0 yet:

http://melabs.com/support/patches.htm#pbp

PBP 2.60A:
Adds support for: PIC12F1822, 12LF1822, 16F1823, 16LF1823, 12F617, 16F722A, 16F723A, 16LF722A, 16LF723A, 18F23K22, 18F24K22, 18F25K22, 18F26K22, 18F43K22, 18F44K22, 18F45K22, 18F46K22, 18LF23K22, 18LF24K22, 18LF25K22, 18LF26K22, 18LF43K22, 18LF44K22, 18LF45K22, 18LF46K22

And I can even use the low voltage versions if I want. WOOT!

Robert

[MOUNTAIN747]

I used the 16F628 and 16F877 before but it looks like I'll have to move up the food chain and the 18F2xK22 and 18F4xK22 series look like just what I need. At least I'm not forced to upgrade to PBP 3.0 yet:

http://melabs.com/support/patches.htm#pbp



And I can even use the low voltage versions if I want. WOOT!

Robert



Robert

Robert, I've got my GLCD working with very little modification to your code. I'm using an 18F45K22. I still have a few bugs to work out with the GLCD code but at least I have something on the screen. The migration to 18F was not too difficult with the exception of a problem I had with ports. my first setup was the same as if I was using 16F and the ports did not work. I then set up ports like this:

asm
;PortA setup
MOVLB 0Fh
CLRF PORTA
CLRF ANSELA
MOVLW 30h ;PortA <5:4> input - Navigator
MOVWF TRISA
;PortB setup
MOVLB 0Fh
CLRF PORTB
CLRF ANSELB
MOVLW 03h ;PortB <1:0> input - Navigator
MOVWF TRISB
;PortC setup
MOVLB 0Fh
CLRF PORTC
CLRF ANSELC
CLRF TRISC
;PortD setup
MOVLB 0Fh
CLRF PORTD
CLRF ANSELD
CLRF TRISD
;PortE setup
MOVLB 0Fh
CLRF PORTE
CLRF ANSELE
MOVLW 0Fh ;PortE <2:0> input - Navigator
MOVWF TRISE
ENDASM

and all works well. I haven't had time to look at Darrel's 'All digital' to see how he handled 18F series but it may be easer to use his include rutine.

Wayne