SD card storage?

#1
I've been over playing with the Propeller chip the last couple months, with the addition of i2c routines, perhaps it would be possible to use the SD card on the PICAXE as well? I see some discussion regarding an onboard BASIC, this would lend a long way to storage for such a project. Has anyone thought along these lines?
 
#2
It seems this is almost all there with picaxe but not quite. If I had a wish list it would be to be able to use either a USB drive or a SD card as an external storage medium for a picaxe. Send the drive a 5 byte address and either read or write a data byte. Simple.

I think it is possible to stream data (eg MP3 music files) using vinculum devices. The costs are still a bit high.

Propeller chips look interesting but I'm not sure I can comment about them on a picaxe forum! Perhaps they will push picaxe towards cheap and cheerful mass storage interfacing. Maybe someone has got this working - I would love to be corrected on the above.

Edited by - Dr_Acula on 24/07/2007 07:18:01
 

jmumby

Senior Member
#3
I have had look at this and found a good tutorial that could get you started but I think the solution is haveing a cheap chip that does all the dog work for you like this <A href='http://www.sparkfun.com/commerce/product_info.php?products_id=7956' Target=_Blank>External Web Link</a> one.
 
#4
chips like that aren't a bad way to go just a pity it isn't in a DIP (&lt;---- see my shfit key does work!) package,
the biggest problem with the picaxe talking to an sd card directly is that there is some kind of un documented timout or somthing of that nature if the commands aren't sent quick enough however this doesn't appear to be the case with the mmc cards
if you ask nicely hippy has some code that works with mmc cards
 
#5
I got sent this link.
I don't know if it's of use to you.
<A href='http://www.fgcvme.co.uk/SDRTC_Prelim_V1.pdf' Target=_Blank>External Web Link</a>
 

hippy

Technical Support
Staff member
#6
I did some work on MMC and DPG did some on SD with a PICAXE but neither of us have so far produced a workable or easy to use solution.

Ideal, multi-purpose interface solutions are usually 'black boxes' which can sit between a PICAXE and whatever is being controlled with a well defined protocol for the PICAXE to use which is PICAXE friendly. Those black boxes can be specialist chips, PICAXE's or other microcontrollers.

I don't see a problem with using Propellers in this way, nor discussion on how they can be used to benefit PICAXE users and how that can be best achieved. It's something I'm planning to do; to provide video output capability for the PICAXE.

Promoting Propeller as something that PICAXE users should be moving to and using instead is a different matter. It's the difference between telling a Ford car owner how to fit an Audi Turbo Charger and encouraging them to scrap the Ford and buy an Audi. People may come to the conclusion that they should perhaps be using a Propeller than a PICAXE, but I don't see that as a serious problem. The PICAXE has its advantages over others and there are plenty of people here already who could use any available micro but still choose to use a PICAXE. In fact, I can see how providing a Propeller to do things the PICAXE cannot will keep people from defecting from the PICAXE camp.

I think a Propeller-based I2C to MMC/SD interface for a PICAXE is a superb idea, especially if the MMC/SD can be made to look just like a 24LCxx I2C Eeprom for the PICAXE programmer. Go for it.

As long as the project sets out to deliver a 'solution', a circuit diagram, build and usage instructions, and a downloadable firmware image, I don't see a Propeller project any different to telling people how to use any non Rev-Ed product with a PICAXE.

When I get my Propellers, an early plan is to produce a firmware loader application so PICAXE users will not even have to use Propeller tools.
 

benryves

Senior Member
#7
I picked up a USB2 SD/MMC card reader from Poundland - it works well when plugged into the VMusic2 USB module. The only problem is that (at least, in the version of the firmware I'm using) the VMusic2 reponds to the drive being added or removed, not the disk being inserted or ejected into the drive.

Some sort of switch that disconnects the 5V USB line when the SD card is not inserted might do the trick. If you aren't going to be changing cards when the device is powered on then it shouldn't be a problem in any case.

&#160;

Edited by - benryves on 24/07/2007 12:36:46
 

hippy

Technical Support
Staff member
#8
<i>I picked up a USB2 SD/MMC card reader from Poundland - it works well when plugged into the VMusic2 USB module </i>

That's good news and presumably it's the see-through yellow &quot;reader&quot; I commented on a while ago which is also a writer.

I thought that was a bargain at the time and it's another way to get access to SD/MMC from a PICAXE via Vinculum, with the added advantage of FAT file system compatibility.
 

benryves

Senior Member
#9
Ah, thanks, I knew I saw someone mention it here but couldn't find the post again. :) Yes, it is the see-through yellow reader/writer.

 
 

Wrenow

Senior Member
#10
Sparkfun also has the chip already on a board with the SD socket and breakout with serial and SPI at http://www.sparkfun.com/commerce/product_info.php?products_id=7955

It is $44.95US, though.

Wreno
 

hippy

Technical Support
Staff member
#11
That's where the Propeller wins, at just $12 USD / 7 GBP, although the cost of board, sockets and firmware I2C eeprom needs adding, and the coding needs doing.

The Propeller can be thought of as a programmable peripheral just as the PICmicro was when it first launched, a software FPGA of sorts. Due to its architecture it can do a lot and often by simply adding an extra socket or component and writing some code. It can do many things at the same time.

I like the notion of boxes which can be used for other things than they normally would, hence my interest in hacking. The Propeller appeals because it's a good cheap solution for enhancing the PICAXE experience. Those who want to play with ( suffer ? ) the complexities of that can do so while delivering easy to use solutions for PICAXE users who just want to use it. Everyone wins.

With a PICAXE oriented Propeller Reference Design, serial and I2C interfacing, that's a good platform for delivering solutions to PICAXE users - Want video ? Add these three resistors and an RCA socket, load this firmware. Want an SD/MCC interface; wire a socket like this, load this firmware. Want a 16x16 LED multiplexor ? And so on.
 

hippy

Technical Support
Staff member
#13
Oops :)

&quot;Leveraging the Propeller experience for PICAXE programmers&quot;

&quot;PICAXE and Propeller synergy for systems designs&quot;

&quot;Convergence of Propeller and PICAXE technology creates new programming paradigm&quot;

One can't beat a good game of Buzzword BS Bingo !
 
#14
Hippy, I thought that was you! I saw someone named Hippy on the Propeller forums and figured maybe, but this just confirms it.

I offer a breakout board to interface a SD card to a Microcontroller. It includes the requisite pullup resistors onboard, and only brings out the necessary signal lines to a header that will plug directly into a solderless breadboard.

It was designed for use with the Propeller, but I believe that any Microcontroller that can do SPI, can interface an SD card. One small issue is the fact that SD cards are really designed for 3.3V. There are various ways of connecting 3.3V devices to 5v devices, but that's another discussion all to itself.

You can see this board at http://ucontroller.com/

Brian
 
#16
Nice to see a few familiar faces. :) Parts-man, I plan to order one of those ucontroller cards. Very Nice work!

I will admit to some PICAXE/Propeller combined projects of my own, as each chip serves well in its own strengths. I'm pleased to see that we aren't repeating the computer wars of the 80's microcomputers. (At least most here aren't!) The intent of my original message wasn't to fuel debate, but I figured with the new i2c access provided by the new chips, that several features had by the &quot;other guys&quot; may become reality for PICAXE as well. I love the idea of harnessing the two together.

Oldbitcollector
 
#17
I am trying to do an SD bsed Data logger with on-board display and came across this:-
<A href='http://www.fgcvme.co.uk/SDRTC_Prelim_V1.pdf' Target=_Blank>External Web Link</a>
beware, its a pdf file if you are a dial-up user.

It suggests its not released yet?
But as it has on-bard RTC, LCD support and can send bitmaps to a GLCD it's ideal for me.
How do you find out:-
a) If it's ready.
b) Where to buy one assuming it's not too expensive?

How do you 'encourage' firms to release a product without ordering 1000s?
 
#18
i actaully got somthing going with an sd card and a pic16f628a but it's dodgy at best and the card i'm using don't seem to be giving me responses that are within the sd standard but i'm still able to read and write to the card if i just ignore the responses to commands, i've since bought a genuine sandisk 1gb card for $20 so i'm rewriting my code , but it'll only work with cards that adhere to the standard like the sandisk ones do, it'll be freeware so anyone with a pic16f628a and a programmer will be able to do their own little 'sd card controller'
 
#19
Thanks dpg. I don't really want 'dodgy' ta.
It's got to be 100% and FAT. No FAT then all you've got is a big EEPROM. And having to upload a meg or two back to PC via PICAXE is a yawn.

Anyway, I'm going to persue the one I mentioned as that sounds ideal. In fact it does just about everything.

I see quite a lot of people here manage to scrounge a sample now and then - I'll try with this.

Edited by - bobelton on 23/08/2007 13:07:57
 
#21
Yes, a 2 month logging period would require a month to download.

When you get BIG you gotta go FAT.

It'll be interesting to see if Bobe can get a free sample.
 
#22
The earlier post by BobElton for the SD data logger led me to contact Frank Eltham at fgcvme.co.uk

This is an excerpt from his email to me:
&quot;We're getting a short run made soon for dealer samples.
Tests so far show 100% for storage/retrieval/library functions and GLCD
operation using PICAXE test software.
We've tried most of the major SD card manufacturers with complete success,
though older/smaller MMC cards have proved unreliable. So, SD only.&quot;

Frank Eltham.

FGC P.O.Box 2509 Wareham Dorset BH20 6YH U.K.
Tel: 44(0) 1929 405388 Fax: 44(0) 8719941420 Email: FGC(AT)fgcvme.co.uk

He also sent along some test code for an 18x and it looks like a definite go.

Here's one wheel we won't all have to reinvent.

It would be great if we could support the efforts of this company. Let's hope Rev-Ed picks up this product.

Arvin

 
#23
Hello Dominic, Saw your posting :&quot;so i'm rewriting my code , but it'll only work with cards that adhere to the standard like the sandisk ones do, it'll be freeware so anyone with a pic16f628a and a programmer will be able to do their own little 'sd card controller'&quot;
Would you please email me &lt;sathkoml@yahoo.com&gt; the details of the SD-CARD project together with the FREEWARE
 

jmumby

Senior Member
#26
I have just landed a dosonchip <A href='http://www.sparkfun.com/commerce/product_info.php?products_id=7956' Target=_Blank>External Web Link</a> just got find the time to get it to work! Bought it when NZ was 80Cents to the US. Got two of those a trackball and two stepper motor drivers for $90NZ. Fat16 &amp; 32 - bonus!
 
#27
i've actauly been that tempted to give up on the whole sd card writing idea mainly due to the trouble i've been having trying to get it to work which isn't easy when the cards themselve don't actaully give responses that they are supposed to

i still have to implement some kind of filesystem thats readable from a pc which will probably be a little difficult to squeese into a pic16f628a, i may have to goto the pic16f88 or somthing with more program memmory

the biggest problem i've had so far is that it'll be 1:30 am i'm red and bloodshot in the eyes when i get it to sucessfully read and write countless times , yet 12 hours later after some sleep i start things up again and nothing works like it should do, it's very weird
 

nbw

Senior Member
#28
Vaguely related / slightly OT maybe...

has anyone tried connecting an IDE hardrive, via an external HDD enclosure with a USB2 socket... to a VMUSIC2??!!
 

sedeap

Senior Member
#29
*********
DPG...
Don't give up !
Don't let that little thing defeat you !
Is only one little SD... spank it !

hehehe <img src="smile.gif" width=15 height=15 align=middle>

:eek:)
 
#30
i think it's time i gave it up,, at least for now with sd cards
same goes with mmc cards

i'm going to look into cf cards as they may be easier to to

i'm going to look back into mmc and sd cards as they might at some time down the track become less critical which is the major problem at the moment
 
#31
DPG you are brave.
Even more wires to connect and if memory (no pun) serves me correctly you have to write a 512 byte sector in a lump in one of the modes, but that was a long time ago so my brain may have been damaged by Fosters in the intervening time.

Ironically, I gave CF up and went for SD and FAT.

Is it my PC or is this forum getting reallly slow?
 
#33
i'm not exactly excited about jumping into cf cards , one of the considerations i'm thinking of is somthing along the lines of the nand128-a basically a raw nand chip like they use in the usb sticks and sd cards although from what i've seen you need yet more io lines but the interface appears to be simpler than an sd card and it doesn't appear to need a complex initialisation sequence the only problem is they only come in surfacemount packages, which may be a problem
 
#34
But are you going to get it to work in FAT and have it as removeable media? (Or meeja as people call it).

I honestly can't see point of non-FAT if you are going to generate huge data files - downloading may be a nightmare.

A big task and top respect. I hope you don't end up spending 6 months re-inventing wheel for the sake of saving $30.
Is it 'the challenge'?
And will it refuse to accept ASCII values 65 to 90? :)
 
#35
i don't see why one wouldn't implement fat,
downloading the data is... yes going to be a pain in the gludious maximus, but i've read an article recently about one manufacturer implementing several normally unused pins to provide an mmc compatible interface
,that would make things interesting

the whole point to it is actaully the challenge of it after looking around in a few of the other forums with a lot of people &quot;saying it couldn't be done with a 16fXXX&quot; so far the results i've gotten out of it say otherwise, i got as far as a fully initialising an mmc card with the 2 correct r1 responses i got a 0 r1 response from a write command several times but can't seem to get that going reliably,
i've got some webspace and an image of the circuit i used i'll post it later on tonight
along with the code



 
#37
i suppose it would help if i spelt it correctly ... google &quot;gluteus maximus&quot; you'll see what it is,

i think we need to start a chat room of somekind so we aren't fillinf up the forum with so much non picaxe talk,, it's starting to get real slow.....
 
#38
It's OK, I know how to spell it and I'm sitting on it's description.
This thread has gone cold anyway.

But I'd love to know why this Forum has gone slow? It's not exactly megabytes.
 
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