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jecottrell
Joined: 16 Jan 2005
Posts: 559
Location: Tucson, AZ
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| LCD Addressing Problems |
 Posted: Mon Jan 29, 2007 4:07 pm |
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Hello All,
I'm fighting with an Okaya RC2004D LCD. The one page datasheet says it has a HD66712U controller... but I'm not so sure.
I've tried PCM's Flex LCD420 driver and neither addressing scheme generates text in the proper places.
I use the following code to test the placement:
| Code: |
lcd_gotoxy(1,1);
printf(lcd_putc, "12345678901234567890");
lcd_gotoxy(1,2);
printf(lcd_putc, "abcdefghijklmnopqrst");
lcd_gotoxy(1,3);
printf(lcd_putc, "!@#$}^&*()+=;:<>?[]{");
lcd_gotoxy(1,4);
printf(lcd_putc, "ABCDEFGHIJKLMNOPQRST");
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With the addressing for 'most' LCDs I end up with:
| Code: |
12345678901234567890
34567890!@#$}^&*()+=
abcdefghijklmnopqrst
mnopqrstABCDEFGHIJKL
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When I use the addressing for the 66712, I end up with:
| Code: |
IJKLMNOPQRST34567890
34567890
!@#$}^&*()+=;:<>?[]{
;:<>?[]{
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Any help would be appreciated.
Thanks,
John |
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jecottrell
Joined: 16 Jan 2005
Posts: 559
Location: Tucson, AZ
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| Posted: Mon Jan 29, 2007 4:51 pm |
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UPDATE:
I don't think it's an addressing problem. Anything after the 13th character gets repeated on line 2? So I'm not sure where to go from here. (That's with the 66712 addressing... I'm going to try the other in just a minute....)
John |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Jan 29, 2007 5:06 pm |
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The data sheet on the Okaya site is very limited.
The way I would try to solve this is to do a web search for other drivers
for this LCD or the HD66712 controller. Quite often there is a Linux
driver available. I did a quick check and some of the drivers do
mention an alternate memory map. I don't have time to look at it
right at the moment but I could do so later tonight, if you or someone
else hasn't solved it already. |
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jecottrell
Joined: 16 Jan 2005
Posts: 559
Location: Tucson, AZ
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| Posted: Mon Jan 29, 2007 5:25 pm |
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Thanks PCM, I'd really appreciate that.
I've figured out that that:
1,1 = 0x00
1,2 = 0x40
But anything above 12 or 0x0C gets put at the right spot on line 1 but also gets repeated starting on line 2!?
John
EDIT:
Here is the datasheet:
http://www.lcd-module.de/eng/pdf/zubehoer/hd66712u.pdf
On pdf page 48 they list some commands that enable four line displays. I'm going to work on it some more when I get into the office tonight. But any help from the expert would be much appreciated. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Jan 29, 2007 11:10 pm |
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It also might be helpful to do a different test. The program below will
display one line at a time. It clears the screen between lines. This way
we don't have to worry about subsequent lines overwriting previous ones.
I have a short delay of one second in between each line. You might
want to remove the delay and put a call to getc() in there instead, for
each one. This would allow enough time to write down the results for
each line.
| Code: |
#include <18F452.h>
#fuses XT,NOWDT,NOPROTECT,BROWNOUT,PUT,NOLVP
#use delay(clock=4000000)
#include "flex_lcd420.c"
//================================
void main()
{
lcd_init();
lcd_putc('\f');
lcd_gotoxy(1, 1);
lcd_putc("0123456789ABCDEFGHIJ");
delay_ms(1000);
lcd_putc('\f');
lcd_gotoxy(1, 2);
lcd_putc("0123456789ABCDEFGHIJ");
delay_ms(1000);
lcd_putc('\f');
lcd_gotoxy(1, 3);
lcd_putc("0123456789ABCDEFGHIJ");
delay_ms(1000);
lcd_putc('\f');
lcd_gotoxy(1, 4);
lcd_putc("0123456789ABCDEFGHIJ");
delay_ms(1000);
while(1);
} |
You could show the results like this:
Line 1 is displayed as:
| Code: |
0123456789ABCDEFGHIJ
--------------------
--------------------
--------------------
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And then do the same type of drawing for the other three lines.
Show how the LCD appears when each line is written to it.
Of course, show the line number addresses that you were using
for the test. |
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jecottrell
Joined: 16 Jan 2005
Posts: 559
Location: Tucson, AZ
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| Posted: Tue Jan 30, 2007 1:14 am |
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This is just a quickie (from memory), I'm at the office away from all the hardware, etc. I will provide a full, detailed report in the morning.
Line one, using memory 0x00:
| Code: |
0123456789ABCDEFGHIJ
CDEFGHIJ------------
--------------------
--------------------
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It looks like maybe the NW bit needs to be set to enable the 4 line mode? I'll try to figure out how to do that. It looks like it's one of the few commands that needs to have the RE bit high? I'll try to mod the lcd init string and post it for a critique....
Thanks,
John
EDIT:
Okaya sent me a datasheet for the controller. They say it's a 34COM/60SEG:
http://www.trash.net/~luethi/microchip/datasheets/lcd/ks0073.pdf
The LCD data sheet says it's a HD66712. I notice there is a slight difference in the init routines between the two.
Last edited by jecottrell on Tue Jan 30, 2007 3:08 am; edited 1 time in total |
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jecottrell
Joined: 16 Jan 2005
Posts: 559
Location: Tucson, AZ
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| Posted: Tue Jan 30, 2007 3:07 am |
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OK, I think I'm getting closer but won't be able to try it for a few hours.
Here is a change to the init lcd string that I hope will fix the problem:
| Code: |
int8 const LCD_INIT_STRING[4] =
{
0x20 | (lcd_type << 2), // Set mode: 4-bit, 2+ lines, 5x8 dots
0xc, // Display on
1, // Clear display
6, // Increment cursor
0b00100100, // Enable RE (extension register)
0b00001001, // Enable four line display mode
0b00100000 // Disable RE (extension register)
}; |
Thanks,
John |
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jecottrell
Joined: 16 Jan 2005
Posts: 559
Location: Tucson, AZ
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| Posted: Tue Jan 30, 2007 9:40 am |
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PCM,
The change to the init string didn't have any result.
Here is the output of you test program:
| Code: |
0123456789ABCDEFGHIJ
CDEFGHIJ------------
--------------------
--------------------
--------------------
--------------------
89ABCDEFGHIJ--------
--------------------
--------------------
--------------------
0123456789ABCDEFGHIJ
CDEFGHIJ------------
89ABCDEFGHIJ--------
--------------------
--------------------
--------------------
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These are in order and addresses for lines 1 through 4 are 0x00, 0x20, 0x40, 0x60.
Thanks,
John |
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jecottrell
Joined: 16 Jan 2005
Posts: 559
Location: Tucson, AZ
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| Posted: Tue Jan 30, 2007 10:36 am |
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OK, the problem is enabling the four line mode. When I use the following kludged lcd_init modeled after the exact sequence in the datasheet (with the addition of the 3 bytes/6 nibbles to enable four line mode) everything appears to work. If anyone would like to offer some help on making it less ugly, I'd appreciate it. I don't have time to figure out the difference between my previous post and this one and why one worked and the other didn't. But it could be the delay after power-up. The datasheet recommends a healthy 30mS in low power system (2.7V).
| Code: |
void lcd_init() {
BYTE i;
set_tris_lcd(LCD_WRITE);
lcd.rs = 0;
lcd.rw = 0;
lcd.enable = 0;
delay_ms(40);
//for(i=1;i<=3;++i) {
lcd_send_nibble(2);
delay_ms(5);
lcd_send_nibble(2);
delay_ms(5);
lcd_send_nibble(0x08); // 0x00 = 1 line, 0x08 = 2 line mode
delay_ms(5);
lcd_send_nibble(0);
delay_ms(5);
lcd_send_nibble(0x0C);
delay_ms(5);
lcd_send_nibble(0);
delay_ms(5);
lcd_send_nibble(0x01); // clear display
delay_ms(5);
lcd_send_nibble(0);
delay_ms(5);
lcd_send_nibble(6);
delay_ms(5);
lcd_send_nibble(2);
delay_ms(5);
lcd_send_nibble(4); // enable RE
delay_ms(5);
lcd_send_nibble(0);
delay_ms(5);
lcd_send_nibble(9); // enable four line mode
delay_ms(5);
lcd_send_nibble(2);
delay_ms(5);
lcd_send_nibble(0); // disable RE
delay_ms(5);
//}
//lcd_send_nibble(2);
//for(i=0;i<=3;++i)
// lcd_send_byte(0,LCD_INIT_STRING[i]);
}
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Thanks,
John |
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