RetroBSD

2.11BSD operating system for microcontrollers
It is currently Fri Jul 19, 2019 8:48 pm

All times are UTC




Post new topic Reply to topic  [ 6 posts ] 
Author Message
 Post subject: SD Cards
PostPosted: Thu Nov 20, 2014 6:54 pm 
Contributor

Joined: Mon Nov 12, 2012 1:34 pm
Posts: 1092
Hi Serge,

Thanks :). Good point. I am waiting until you say go!

Not sure how to create a new topic. Just 'fixed' a 4GB SD card I tried on RetroBSD and thought I 'fried' it.

But my camera 'knew' how to 'fix' it ??!! I told camera to reformat it ??!!

So my question is: Does the RetroBSD driver work with SD cards greater than 2GB? If not, can it easily be fixed. And wouldn't it be neat to be able to dump an SD card's internal program with Retro and reprogram the SD card to be more useful to RetroBSD :).

Has anyone done this?

And can they spill the beans as to how to do it?

The SD card might be a pretty good co-processor for some tasks ?

Wiz


Top
 Profile  
 
 Post subject: Re: PIC32MZ - news ??
PostPosted: Thu Dec 04, 2014 5:02 am 
Committer
User avatar

Joined: Wed Oct 10, 2012 11:01 pm
Posts: 1081
Location: Sunnyvale, CA
Yes, RetroBSD can work with SD cards of size 4Gb and more. These are usually called SDHC cards. They have slightly different i/o protocol.

BTW, some variants of PIC32MZ became available in stock on microchipdirect.com:

PIC32MZ2048ECG064-I/PT
PIC32MZ2048ECM064-I/PT
PIC32MZ2048ECG100-I/PF
PIC32MZ2048ECH100-I/PF
PIC32MZ2048ECM100-I/PF


Top
 Profile  
 
 Post subject: Re: SD Cards
PostPosted: Thu Dec 04, 2014 1:39 pm 
Committer
User avatar

Joined: Thu Oct 11, 2012 8:45 am
Posts: 1801
Location: Room 217, Floor 8, Arm 8, Wheel S7, Mars Base Alpha 3
wiz wrote:
Not sure how to create a new topic.

You press the Image button. What could be simpler?

_________________
Why not visit my shop? http://majenko.co.uk/catalog
Universal IDE: http://uecide.org
"I was trying to find out if it was possible to only eat one Jaffa Cake. I had to abandon the experiment because I ran out of Jaffa Cakes".


Top
 Profile  
 
 Post subject: Re: SD Cards
PostPosted: Thu Dec 04, 2014 11:41 pm 
Contributor

Joined: Mon Nov 12, 2012 1:34 pm
Posts: 1092
Hi Matt,

If I had brains, I would be dangerous :).

Just got some 16GB SD cards. Amazing amount of memory in such a small size.

During my early RetroBSD days, I cleared the first block of a 2gb card (with the FAT in it). I now almost have that card recovered.

Is there a simple way to reconstruct the missing FAT? I haven't found one yet. So, Matt what is your technique?

Wiz


Top
 Profile  
 
 Post subject: Re: SD Cards
PostPosted: Thu Dec 04, 2014 11:59 pm 
Committer
User avatar

Joined: Thu Oct 11, 2012 8:45 am
Posts: 1801
Location: Room 217, Floor 8, Arm 8, Wheel S7, Mars Base Alpha 3
It's called "formatting". I'd recommend the official SD formatter: https://www.sdcard.org/downloads/formatter_4/

But then I don't think you mean you cleared the FAT. The FAT isn't in the first block. That is usually the partition table / MBR. None of which are critical to the operation of the card, and formatting puts them back in.

During normal RetroBSD installation you overwrite that data anyway.

_________________
Why not visit my shop? http://majenko.co.uk/catalog
Universal IDE: http://uecide.org
"I was trying to find out if it was possible to only eat one Jaffa Cake. I had to abandon the experiment because I ran out of Jaffa Cakes".


Top
 Profile  
 
 Post subject: Re: SD Cards
PostPosted: Fri Dec 05, 2014 3:33 pm 
Contributor

Joined: Mon Nov 12, 2012 1:34 pm
Posts: 1092
Hi Matt,

I should have been clearer.

I zeroed blocks 0-3ff. Probably one physical block on that SD not one logical block And this included the FAT and quite a bit of other stuff.

So LOTS of zeroes....

I have noticed that the camera (with its limited brains) stores pictures apparently in physical blocks. So the pictures begin with a block aligned few bytes and end with a LONG string of zeroes and are basically of the same length (more or less).

So it appears to be not too hard to extract the pictures and the names were sequencial!!

I have manually extracted a few pictures and they display fine :).

The only real question concerns 'other' files. From my preliminary analysis there were some such files. i.e.- Not all files begin with the jpeg bytes and end with lots of zeroes. Maybe this will do for a first pass? Anyways I figured you might have had to do the same thing and wondered what you might have discovered? ASCII verses binary, etc.

At the time I only had a few SD devices so they got used for multiple types of files.

Happy holidays to all.

Wiz


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 

All times are UTC


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
cron




Powered by phpBB® Forum Software © phpBB Group

BSD Daemon used with permission