PIC to SD Card

temtronic · Posted: Thu Aug 11, 2011 8:30 am

Whoa !!!
If your changes appear in Hexedit, then it's NOT your problem ! Notepad has a few 'quirks'.

Trust Hexedit.

Ttelmah · Joined: 11 Mar 2010 Posts: 19541

Have to agree.
Had a delicious time trying to track a data problem. An XML string, which appeared absolutely perfect in Notepad (and also in the textedit app on a Mac), but would not work.
Turned out the characters were using unicode, and looked correct in these text editors, but had completely the wrong values, when you looked in hexedit.
Hexedit shows byte by byte, what is in a file. Notepad, gives a 'text approximation', which can often be wrong....

Best Wishes

sjharris · Joined: 11 May 2006 Posts: 78

I have found that in sector 0x18 the files have their lengths in bytes stored as here
http://www.ecgf.uakron.edu/grover/web/ee470/labs/SDCardMap.pdf
I have managed to read this whole sector into the PIC, search for the file name and increase the number of bytes. This seems to work.
All I want to do now is to make new files on the PIC.
Anyone any ideas??
Cheers