MicroSD can't read individual byte address

tidushuu · Joined: 29 Sep 2012 Posts: 8

I got a terrible problem in MicroSD interface with pic18F4620.

When I try to read each byte address in microSD, example my code

temtronic · Posted: Wed Oct 31, 2012 12:07 pm

Without more information it is really hard to tell you where your problem is.
Hardware issues include mismatched voltages(5V PIC, 3V sd card),incorrect level translations,improper layout,etc.
Software issues include initialization routines,addressing,card select,timing,etc.
2 or 3 lines of code isn't anything solid of anyone to really comment on where the problem is.

This all assumes you've read/written to the card on a PC with KNOWN data.

The more info you supply( schematic,size of card(make/mfr/etc.),main program the better(quicker) we can help.

hth
jay

tidushuu · Joined: 29 Sep 2012 Posts: 8

Thanks for reply.
About my hardware, its correct because a few weeks ago I could run with my SD card wtihout any problems. Now I use micro SD, I can still get mmc_init and reset work well, but when I read individual byte address, I can't get value I need.
I think microSD always return back 512 byte value address, so I must change whole my code for this if I can't solve this problem.

asmallri · Joined: 12 Aug 2004 Posts: 1634 Location: Perth, Australia

Could it be the first card you tested was standard capacity and the microSD card is SHDC?
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