SD Addressing

Does anyone here understand how block addressing addressing works on SD (secure digital) cards? I have a card that is FAT16.... and I can initialized the card with my HC11, and can read 512 byte blocks of data from it... however I can't understand how the addresses I'm using work.

It seems that no addresses will work untill address 0x200.... then only multiples of 0x200 will work after that. This makes some sense I guess, as 0x200 is 512 in decimal... so I guess I'm addressing blocks of 512 bytes? But the confusion comes in when I try to look at my SD card in HEX on my computer... the offsets don't seem to match up and I'm unable to figure out how to get to a certain offset in the card from the HC11. For instance, I know that a text file is stored starting at 0x6A00 .

Anyone have some hints for me on this? I've never done any programming with FAT's so maybe it's something universal to that and not specific to SD cards.

Reply to
TheRain
Loading thread data ...

Nevermind, I was looking at the card as a logical disk on my computer, which makes 0x00 the start address of the logical drive, and not the physical disk... I found a hex editor, WinHex that let's you look at it as a pysical disk as well.

Take a look at this discussion for some really good information

-->

formatting link

Reply to
TheRain

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.