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| HD44780, how to program and display user defined characters? http://forum.lcdinfo.com/viewtopic.php?f=9&t=1699 |
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| Author: | washburn_it [ Sat Sep 02, 2006 15:26 ] |
| Post subject: | HD44780, how to program and display user defined characters? |
Hi, I have a 8x2 LCD display equipped with a HD44780. Everything is working fine and since there is no functionality to reverse the characters I thought that I could create "user defined font" with all the characters reversed and then "upload" them to the HD44780 everytime my program run, after the initialization. Actually I need to reverse only characters from "0" to "9" and the " " (space). Reading the datasheet it seems it's possible but, unfortunately, it's not so clear how to do that. Then I'm asking the experts how I can do that considering that I'm using the display in 8-bit mode. Thank you, regards. Bob |
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| Author: | washburn_it [ Sat Sep 02, 2006 19:20 ] |
| Post subject: | |
I tried the code below to redefine the character 0 but it doesn't work: LPT= 0x0378 // set the CGRAM at the address 00 portwriteb(LPT, $40); portwriteb(LPT+2,E_1 or RS_0); delay(1); portwriteb(LPT+2,E_0 or RS_0); // this is the cycle where the character pattern is passed to the // display 7 times, one for each row of the character matrix. // At the end character 0 should display 3 vertical lines for c:=0 to 7 do begin portwriteb(LPT, $15); // <-- bit pattern portwriteb(LPT+2,E_1 or RS_0); delay(1); portwriteb(LPT+2,E_0 or RS_0); delay(1); end; Where's the mistake? Regards, Bob |
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| Author: | washburn_it [ Mon Sep 11, 2006 15:06 ] |
| Post subject: | |
I found it...I should have put RS=1 instead of RS=0. I hope it helps other users, regards. Bob |
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