LCD vexation

[dennis8437]

I am having an LCD issue that is beating me up. I have a project that works with a small LCD display but when I put a larger display on it, it doesn't work. The upper half of the display is 20 solid boxes, and the lower half is blank. I am using the 16F690 MCU and PICBASIC PRO (program sample zipped and attached). The small yet functional LCD Display is a TRULY MCC162B3 16X2 and the larger one is a CRYSTALFONTZ CFAH2002L-YYH-JP 20X2. The CRYSTALFONTZ unit works fine when I duplicate the demonstration in the LCDOUT section of the PBP manual (using a 16F84a). I have checked my connections many times and played with the timing parameters. I am stuck.
Thank you
Dennis

[Charles Linquis]

You say you have changed the timings, but I don't know how far you have gone. I use a wide variety of LCDs, and find the following parameters work with all of them.

DEFINE LCD_COMMANDUS 2500
DEFINE LCD_DATAUS 200

[mister_e]

what happen when you play with the contrast voltage?
What if you use..


Start:
PAUSE 2000
LCDOUT $FE,1,"Hello"
Here: Goto here


how about the usual..
is a simple Led Blink work
How about your config fuses
how about your crystal speed

Sorry to asked but sometimes we have ;)

[dennis8437]

I just tried your ideas but to no avail. I previously tried several values for COMMANDUS and DATAUS out to 5000 and 250 µS each. I also tried several PAUSES of 1000 to 5000 mS in various spots in the program. I didn't try mister e's idea, though, because I think that I need the list of DEFINES to make the 16F690 work. Right? This display did work with a 16F84a and a simple program like that one.
Thank you for your consideration,
Dennis

[mister_e]

I hate that datasheet... see table 9-2

ANSEL=0 will solve the problem.

[dennis8437]

Dear mister e,

That was it!! Thank you so very much. I did use the ANSEL = 0 but on a bit level. I guess that maybe I over thought it, or not. Again, thank you.

Best Regards,
Dennis