lcd_getc(x,y) don't work?

[dendenden98]

Hi,

When I use my LCD program with lcd_getc(x,y) functions in PROTEUS. My program is run very good. But when I work in real circuit all of the other LCD functions runs, but lcd_getc(x,y) didn't. For example;

char ch;
....

printf(lcd_putc,"\fHello");

ch=lcd_getc(2,1);

printf(lcd_putc,"\n%c",ch);

delay_ms(1500);

I see in LCD:

1. Line=Hello
2.Line=_ (I see bold rectangle in this cursor. Normally I should see 'e' character. I see 'e' character in PROTEUS, but I don't see 'e' character in the real circuit)

[temtronic]

Quick comments

Do you have the LCD properly wired up? Show us your schematic of your hardware NOT the Proteus 'schematic'.

What PIC, compiler version, LCD driver ?

What LCD module? Have you the correct timing sequences for that LCD?

[dendenden98]

I wired up LCD correct. Because, other LCD functions are runs good. Only lcd_getc(x,y) functions don't run. I use lcd.c driver in PIC C directory. I use PIC16F877 and I try 2x16 character LCD. My compiler version is 4.107. I don't know I have correct timing for LCD. But all LCD functions runs in LCD driver except lcd_getc(x,y).

[Ttelmah]

Seriously, _try it with a real chip_.

I have Proteus, hundreds of versions, right up to the latest 7.9 beta. Love it as a schematic design/PCB package, and it's analog simulation is also good, _but_ it's PIC emulation, and that of many digital peripherals, is not reliable, and not worth using in general. I'd suspect that Proteus, is simply not emulating the data read operation from the LCD, which is why it won't work for you.

flex_lcd, can be configured to be 'write only', not using the R/W line, in which case the read function won't work, but the standard LCD driver, _requires_ data returns from the chip, reading the 'busy' status line. So all your operation have to be working, it is just that you are not getting the character data back - hence the suspicion that the emulation does not do this correctly - few people ever use the read function (after all if you send data to the LCD, you know what should be there!.....), so it is probably just something that Proteus does not bother to emulate.

Best Wishes

[dendenden98]

[Ttelmah]

Use a real chip...

[dendenden98]

I already use real LCD. I can't understand exactly what you mean that you say use a real chip.

[PCM programmer]

I made a test program from your code, and I used the CCS lcd.c driver
that comes with vs. 4.107, and I ran it on a PicDem2-Plus board (red vs.)
and it works. Here's the output:

[dendenden98]

Thanks PCM Programmer. I re-build my LCD connection and it's run. But I don't understand in my old circuit, all LCD function runs except lcd_getc() function. But now I re-build my LCD connection and lcd_getc() function is run in addition to other LCD functions. interesting.

Thanks to all who respond.