Problems with LCD driver

Ares · Guest

I have this code in a test program,but it doesn't work,leds don't shine.Port B is configured in the "LCD.c" archive as output for the LCD,but LCD it is not conected because i haven't any.Could it be that the problem?."LCD.c" arhive is the one on the original CCS PIC C Compiler progam,any change was made.

Thank you for your help.

#include <16F877.h>
#use delay(clock=4194304)
#fuses HS, NOWDT, NOPROTECT, NOPUT, NOBROWNOUT, NOLVP
#byte port_c=7
#define led1 PIN_C2
#define led2 PIN_C3
#include <lcd.c>

void main()
{

lcd_init();
set_tris_c(0x00);
port_c=0;
lcd_putc("Look this leds");

do
{
output_high(led1);
output_low(led2);
delay_ms(3000);

output_low(led1);
output_high(led2);
delay_ms(3000);

}while(true);

}

Haplo · Joined: 06 Sep 2003 Posts: 659 Location: Sydney, Australia

When you debug the code, does it get passed lcd_init()? What happend when you comment that line?

Ares · Guest

C-H Wu · Guest

All your problems comes from the following line in lcd_send_byte() of CCS's driver, LCD.C:

while ( bit_test(lcd_read_byte(),7) );

if your LCD is not connected, then you will end up hanging in the while loop. I modified it with a timeout break like this

while ( bit_test(lcd_read_byte(),7) )
{
delay_us ( 5 );
if ( --i == 0 )
{
lcd_fail = TRUE;
break;
}
}

such that I can live with, or without, the LCD, or, with a dead LCD.

best wishes

djpark · Joined: 02 Mar 2004 Posts: 49

Ares · Guest

Thank you,both of you for your help.I really feel more calmed now I know wich the problem was.I hope it will work with the LCD....hehehe.
Best wishes

Guest · Posted: Thu May 13, 2004 5:09 pm

try sticking in the following

printf(lcd_putc,"whatever");

RatFink · Joined: 01 May 2004 Posts: 49

I also have trouble with this driver using it with a crystalfontz LCD. I don't understand why they would make it use the Port B knowing that it cause problem with the ICD.

MGP · Joined: 11 Sep 2003 Posts: 57

RatFink · Joined: 01 May 2004 Posts: 49

Mc · Joined: 07 May 2004 Posts: 11

I use an adaptation of this one:

http://www.vermontficks.org/lcdd.htm

Have a look Wink

Guest · Posted: Sat May 15, 2004 4:49 pm

if your using the icd development board heres the reason why it does't work.

*********************************************************
Brian,

The pins 39 and 40 are not connected on the board other than to the ICSP socket since these pins need to be isolated during in-circuit programming.
Circuitry on these pins can cause corruption of the programming bitstream and clock. It may be possible to use the CCS complier's LCD functions with another port, however we are not familiar with the LCD section of the CCS compiler.

Best Regards,

UK Techhelp

INTERNET ACCESS
World Wide Web address -http://www.microchip.com/
FTP address - ftp://ftp.microchip.com/
*************************************************************
i have some source code which use port D, you can download it here:
(i didn't write them, but have used them and they work fine)

http://home.t-online.de/home/Matthias.Stehr/hoehe.htm

RatFink · Joined: 01 May 2004 Posts: 49

young · Joined: 24 Jun 2004 Posts: 285

I used C-H Hu and Djpark's method modified ares's program, however, I did not got the lcd display characters, but the rb7 led turns on. what is wrong with my code. my hardware is 26f877a, lcd connected to portb and every connection comes from the easy2 board, I did not change anything? advice please, and I also post the testing file provided by ares at "2X16 LCD on pic16f877a portb" post.

Thanks
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E YILMAZ · Guest

Thank you C-H Hu!