mmcsd and fat libs of CCS don't work?

temtronic · Posted: Fri Dec 16, 2011 1:10 pm

1a) Get rid of all resistors except the 2 pullups on the sdcard. ADD correct level shifter( translator) IC .

1b) CCS code is good.

2) See 1a above . Use correct level shifter IC, unless you're good at selecting the correct transistors and bias resistors for the Vcc5, Vcc3,current demands,speed, etc.

3) You're right, it will NOT work. Simple elementary logic level stuff, as previously stated 3.3v from sdcard is NOT a logic one for the PIC. You MUST have at LEAST 4.0 volts(80% of Vdd if 5 volt PIC).

4a) This is NOT a software problem and cannot be fixed by using a 'driver' from another library( if using hw spi).Unless you design a custom driver using the adc pins.

4b) see 3) above. PIC is only seeing zeros never any ones !

tesla80 · Joined: 23 May 2007 Posts: 81

Guys thanks for all your suggestions, I resolved the HW problem as you said and it now receives data from the card.

Can anyone answer to my question at: http://www.ccsinfo.com/forum/viewtopic.php?p=155266#155266

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

As you have learned, most people that post in the Code Library forum
don't want to answer questions. Or they may not even be active on the
forum any more.

With regard to your question in the link, it looks like you want to reduce
the array size to only 64 elements (from previous size of 512). But then
you try to compile lines that access the array at index 0x1C6.
Then you get "subscript out of range" for sure, because the index 0x1C6
is way beyond the last element, which is 63 (0x3F in hex).

tesla80 · Joined: 23 May 2007 Posts: 81

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

I don't know that much about it. A quick easy solution is just to buy
asmallri's FAT code. Our company bought his SD card tester code and it
works. We didn't try his FAT code yet, but other people have bought it
and say it works well. You can spend days on this problem, or weeks.
If speed of development is important, I suggest buying his code. His
company link is in his sigline.

tesla80 · Joined: 23 May 2007 Posts: 81

You are right for totally not working systems but I need only a little bug fix in that code. I need to create many files in the card but when I can't write to some of them its bad... I need to solve this.
Maybe the solution is in the write block function, if someone helps me we could have another bugfree code here as forum

asmallri · Joined: 12 Aug 2004 Posts: 1630 Location: Perth, Australia

temtronic · Posted: Wed Dec 21, 2011 6:50 pm

If you get really,really frustrated with SD card software you can always buy a Vinculum flashdrive module for $30 and not have to worry about the 'low level' aspects of file management.

It all depends on what your time is worth,when the project is due,amount of data storage, etc.

From a data management perspective,if you only want 64 bytes of data per file, just group 4 of your logical files into one physical file.

In the old days (late 70s) it was very common to have 3 ,85 byte 'records' stored into one 256 byte file. Very efficient use of the then very,very costly floppy disc space.The math to 'parse' the physical record into logical is trivial.Any TRS-80 gut will know what I'm talking about !

The bottom line you either have to pay with time or money.Time to either work out the solution or find using Google....money to buy either the product already made or have someone else do the work.