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young
Joined: 24 Jun 2004
Posts: 285
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| is my LCD dead? |
 Posted: Fri Dec 09, 2005 9:34 am |
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I used a 2x16 segment LCD and used lcd.c driver provided by ccs. I was able to write to the lcd long time ago using the following setup
PortB LCD
B7 D7
B6 D6
B5 D5
B4 D4
B0 Enable
B1 Rs
B2 Rw connected
however, is time I could not see anything on my lcd, it is blank, nothing happened to it, just like a lcd without connecting with anything? what might happened?
the following is a thread that I worked on lcd a long time ago!
[url]
http://www.ccsinfo.com/forum/viewtopic.php?t=19769&highlight=lcd[/url] |
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Ttelmah
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| Posted: Fri Dec 09, 2005 10:51 am |
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What have you got connected to the LCD bias voltage pin?.
What has to be here, varies with different makes/types, with some working with a +ve voltage and some (generally older) types requiring a
-ve voltage. Unless this voltage is in the right range, you will see nothing on most LCD's.
Best Wishes |
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wolverine_349
Joined: 07 Dec 2005
Posts: 6
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| Posted: Fri Dec 09, 2005 11:27 am |
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Dude ,you sure u varied your contrast and checked ur voltage levels?i am currently working on 16x1Lcd which wasn't working until i changed the contrast n i saw all that i missed .  .is the LCD module having a hitachi HD74880 based controller or wot.
since u r using 4bit mode ,make sure data transfers are done twice.wud b good if u verify that first.
good luck |
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young
Joined: 24 Jun 2004
Posts: 285
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| Posted: Fri Dec 09, 2005 11:53 am |
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Thank you:
which pin is LCD bias voltage pin?
I have a contrast pin Vo pin setup, and no matter how I adjust my contrast, it still show nothing? |
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young
Joined: 24 Jun 2004
Posts: 285
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| Posted: Fri Dec 09, 2005 12:24 pm |
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| Ve=Vo |
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young
Joined: 24 Jun 2004
Posts: 285
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| Posted: Fri Dec 09, 2005 12:38 pm |
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my lcd came with a development board which Vo(Ve) is setup as pluse, no negative voltage, even I tried the testing program came with the board, it would not show anything!
any other suggestions? please? |
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wolverine_349
Joined: 07 Dec 2005
Posts: 6
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| Posted: Fri Dec 09, 2005 12:45 pm |
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could u post some of ur code here.also c if u can put link to the datasheet or something like that ,to know the LCD controller,and the display's electrical configuartion
good luck |
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young
Joined: 24 Jun 2004
Posts: 285
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| Posted: Fri Dec 09, 2005 1:24 pm |
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| Code: |
#if defined(__PCM__)
#include <16f76.h>
#fuses HS, NOBROWNOUT,NOWDT,NOPROTECT,NOPUT
#use delay(clock =8000000)
#use RS232(baud=9600, parity=N, xmit=PIN_C6, rcv=PIN_C7)
#include <lcd-1.c>
main()
{
lcd_init();
delay_ms(200);
printf("Pulse width measure ready!\r\n");
while(1)
{
printf("Waiting signal\r\n");
printf(lcd_putc, "Waiting for start!");
delay_ms(1000);
}
}
The board is from Mikro, easypic2, old version, newer one is easypic3. the lcd is CMC216NO2 |
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young
Joined: 24 Jun 2004
Posts: 285
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Ttelmah
Guest
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| Posted: Fri Dec 09, 2005 3:50 pm |
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Stick a delay in before the LCD_INIT call. Some current LCD's, are very slow indeed waking up, and LCD_INIT can be too quick on these.
Best Wishes |
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young
Joined: 24 Jun 2004
Posts: 285
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| Posted: Mon Dec 12, 2005 4:15 pm |
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Thank you everybody:
I bought another LCD from digikey, the new part works fine, I can see the character. thank you all! |
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