Need help with ROM and managing large files

osu1177 · Joined: 10 Feb 2011 Posts: 14

Hi,
I am trying to interface my pic16f877a with a knockoff nokia LCD. I have had success with everything except displaying characters, text, or bmp files, simply because it requires you to link to a larger file, and I am having difficulty doing that.

When I link a header file with the char bmp file, I get an error "out of ROM, a segment or the program is too large." Additionally, I see the following:
"Seg 00004-007FF, 07FC left, need 661F
Seg 00800-00FFF, 0800 left, need 661F
Seg 01000-017FF, 0800 left, need 661F
Seg 01800-01FFF, 0800 left, need 661F
Seg 00000-00003, 0000 left, need 661F"

According to many searches here, the answers range from using #separate, to splitting up code, or managing where in ROM the large files are stored. I believe its the latter, since the .sta file indicates i am using only 4% of my rom.

I am somewhat new to programming, and would greatly appreciate any thoughts which could guide me in the right direction.

My compiler version is 4.057.

Here is the routine which calls on the char in bmp.h:

Ttelmah · Joined: 11 Mar 2010 Posts: 19559

The problem is the file you are trying to load....
The '4%', is without this.
The chip has a 'grand total' of just 8192 words of storage. The file wants 26143.....
As it stands, it is not going to fit. No amount of juggling will make it fit. Your only hope would be to put this extra data into an _external_ memory (EEPROM?), and just read the stuff from this as needed. It sounds as if this data is things like character maps, which will only need speed when reading, so something like an EEPROM should do this OK.

Best Wishes

osu1177 · Joined: 10 Feb 2011 Posts: 14

Thank you Ttelmah, for your quick and courteous response. I will add an EEPROM to my circuit and continue from there.
Regards,
David

osu1177 · Joined: 10 Feb 2011 Posts: 14

Hi Ttelmah,
Are you aware of any resources which would help me find a suitable EEPROM? I need plenty of space, as I hope to evolve my simple character maps to animations. I am also quite new to this, is there sample code I could look at to help me establish communication with the EEPROM?
Regards,
David

temtronic · Posted: Mon Feb 21, 2011 3:27 pm

code examples can be found in the examples folder wherever you installed the compiler on your machine

osu1177 · Joined: 10 Feb 2011 Posts: 14

Thanks temtronic. Are there any suggestions as to specific memory chips I should look into, preferably ones whose use is well documented?

dyeatman · Joined: 06 Sep 2003 Posts: 1937 Location: Norman, OK

Try FRAM, it is 500x faster than EEPROM and it will make a huge difference
when writing large files. I use FRAM exclusively now...

http://www.ramtron.com/about-us/what-is-f-ram.aspx
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