Post by thread:[PIC]: Reduce flicker on Graphic LCD?

Hi everyone, How do I reduce the flicker on my graphic LCD? This is basically how I control the LCD: while (1) { clear_LCD(); // Write 0 to the entire LCD RAM write_stuff(); } The reason why I have to clear the entire LCD was if I don't, the stuff from the previous screen is still there (if it is not overwritten) and I think this is the source of my problem, but I don't know how to get by this. Please help! Best regards, Thomas __________________________________ Do you Yahoo!? Yahoo! Search - Find what you re looking for faster http://search.yahoo.com -- http://www.piclist.com hint: To leave the PICList spam_OUTpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu

Wouter van Ooijen wrote: > Don't clear, just make sure that you (re) write all positions. That will work, but you should also structure your code so that you only write the LCD when something actually changes. i.e. not in a tight loop like you illustrated. Jim > -- > http://www.piclist.com hint: To leave the PICList > piclist-unsubscribe-requestKILLspammitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList .....piclist-unsubscribe-requestKILLspam.....mitvma.mit.edu

It is a little more complicated. Let's say I have these codes: data = 12345; printf("%d",data); // LCD scr displays "12345" data = 9; printf("%d",data); // LCD scr displays: "92345" for the second printf, instead of displaying "9", it diplays "92345". It is hard to calculate how many digit the "data" field has to provide the blank space.This is the reason why I have to clear the entire LCD to get rid of this kind of problems. I thought of keeping an image of the LCD on RAM, but this requires lots of RAM space. Regards, Thomas __________________________________ Do you Yahoo!? Yahoo! Search - Find what you re looking for faster http://search.yahoo.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Thomas wrote : > It is a little more complicated. Let's say I have > these codes: > data = 12345; > printf("%d",data); // LCD scr displays "12345" > data = 9; > printf("%d",data); // LCD scr displays: "92345" Hi. I'm not sure what C compiler you use, but does it accept the following : data = 12345; printf("%5d",data); data = 9; printf("%5d",data); That should provide with "padding" with space characters up to 5 characters total. Not sure if it will be left or right padding.... Regards Jan-Erik. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

That should work. But if you are only using a couple of formats, I have found it is better not to use printf. For example, I use 3 digits with or without a decimal place. The routine that does the equivalent of printf("%5d",data); is quite a bit smaller since it doesn't have to handle float, hex, etc. I had to decide to store some numbers with an implied decimal place, but it was well worth it. Bruce Partridge http://www.rebreather.ca > {Original Message removed}

Not certain about type of your graphic LCD but I solved the problem lately by using the second memory. If your LCD display has enough memory for two screens like mine, you could write to the second part and after finishing writing easily change the offset. Regards Igor Thomas wrote : > It is a little more complicated. Let's say I have > these codes: > data = 12345; > printf("%d",data); // LCD scr displays "12345" > data = 9; > printf("%d",data); // LCD scr displays: "92345" -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

{Quote hidden}>-----Original Message----- >From: Thomas [EraseMEthomasn102spam_OUTTakeThisOuTYAHOO.COM] >Sent: 07 March 2004 17:58 >To: PICLISTspam_OUTMITVMA.MIT.EDU >Subject: Re: [PIC]: Reduce flicker on Graphic LCD? > > >It is a little more complicated. Let's say I have >these codes: > data = 12345; > printf("%d",data); // LCD scr displays "12345" > data = 9; > printf("%d",data); // LCD scr displays: "92345" >for the second printf, instead of displaying "9", it >diplays "92345". It is hard to calculate how many >digit the "data" field has to provide the blank >space.This is the reason why I have to clear the >entire LCD to get rid of this kind of problems. I >thought of keeping an image of the LCD on RAM, but >this requires lots of RAM space. >Regards, >Thomas One thing to check is if the display module has enough memory for two pages (some of them definitely do). If it does you can perform operations on the non-displayed page, and then update the display by setting the memory address of the displayed page (aka double buffering). On a more basic level, you could simply clear a whole text line in the display where you are going to update a value, rather than clearing the whole display which can take a significant amount of time. e.g. data = 12345; printf("%d",data); // LCD scr displays "12345" printf(" "); // clear line data = 9; printf("%d",data); // LCD scr displays: "92345" Regards Mike ======================================================================= This e-mail is intended for the person it is addressed to only. The information contained in it may be confidential and/or protected by law. If you are not the intended recipient of this message, you must not make any use of this information, or copy or show it to any person. Please contact us immediately to tell us that you have received this e-mail, and return the original to us. Any use, forwarding, printing or copying of this message is strictly prohibited. No part of this message can be considered a request for goods or services. ======================================================================= Any questions about Bookham's E-Mail service should be directed to @spam@postmasterKILLspambookham.com. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics