LCD problem

[cheptronics]

<font face="Courier New" size=-1>Hello

I use the Software Prototyping Board + ICD programming module with a PIC16F877 and CCS C-Compiler.

I connected a compatible LCD backlit screen to the LCD port on the SPBoard but when I run programs using an LCD nothing is displayed on the LCD screen (and the screens doesn't light), including when I use the "ex_lcdkb.c" example program.

What are the known causes for non-displaying on a LCD screen, except the following ones :
-forgetting the "#include <lcd.h>" line
-forgetting to remove the ICD programming module before running the program
-connection error
-using an incompatible or broken LCD
?

NB : my screen is a Powertip PC1602-L (2x16, backlit) ; I also use a PC1601 (1x16, non-backlit).


Thank you very much,

chep </font>
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This message was ported from CCS's old forum
Original Post ID: 12277

[nilsener]

Dear Chep,

PC1602-L:

check the contrast voltage at Pin 3 (Vo). You can get the required voltage from the datasheet. Notice that the voktage is referenced to the positive supply voltage for the logic. I think you can connect Pin 3 (Vo) to ground to get a reasonable contrast.

The backlight LED's must be supplies via Pin 15 and Pin 16 separately. Notice the high current consumption for the backlight, in this case approx 120 mA / 360 mA ! check the datasheet.

regards nilsener


:=Hello
:=
:=I use the Software Prototyping Board + ICD programming module with a PIC16F877 and CCS C-Compiler.
:=
:=I connected a compatible LCD backlit screen to the LCD port on the SPBoard but when I run programs using an LCD nothing is displayed on the LCD screen (and the screens doesn't light), including when I use the "ex_lcdkb.c" example program.
:=
:=What are the known causes for non-displaying on a LCD screen, except the following ones :
:=-forgetting the "#include <lcd.h>" line
:=-forgetting to remove the ICD programming module before running the program
:=-connection error
:=-using an incompatible or broken LCD
:=?
:=
:=NB : my screen is a Powertip PC1602-L (2x16, backlit) ; I also use a PC1601 (1x16, non-backlit).
:=
:=
:=Thank you very much,
:=
:=chep
___________________________
This message was ported from CCS's old forum
Original Post ID: 12299

[cheptronics]

:=Dear Chep,
:=
:=PC1602-L:
:=
:=check the contrast voltage at Pin 3 (Vo). You can get the required voltage from the datasheet. Notice that the voktage is referenced to the positive supply voltage for the logic. I think you can connect Pin 3 (Vo) to ground to get a reasonable contrast.

Thank you. This is the same for the PC1601.
I just didn't remember that maximal contrast is obtained with 0V in pin 3 and minimal (no display) with over 1V. I think I did the inverse and I put the 3rd pin of the LCD to +5V before my post.
___________________________
This message was ported from CCS's old forum
Original Post ID: 12317