4D Systems and Products

[Marcwolf]

Hi Folks.
A few weeks ago I brought a 4D System uDrive - Dr Acula did a very good review on this when he showed how to hook 64mb's of dataloggind onto an 08M

Unfortunately I ran into difficulties where I was supplied a faulty SD Ram card - which in the process of isolating the issue I also damaged my uDrive.

I contacted 4D Systems with my issues and they most kindly sent out not only a new uDrive, but 2 SD Ram cards as well free of charge. In all my emails and interactions they were extremely helpful, and I have nothing but praise for their efforts.

They have a range of products that are ideally suited for use with PicAxes, generally communicated via a simple serial communication.

Atilla - the manager there - is looking for people who might be interested in showcasing some of their graphical OLED products, and helping show what they are capable of. If you contact him - explain what you are planning to do and he will beable to give you a significant discount on the parts.

You can see more about 4DSystems here http://www.4dsystems.com.au/

I hope someone finds this interesting. Unfortunately my current projects are not graphically orientated otherwise I'd certainly be looking at giving them a try.

As a side note - I am not recieving any renumeration etc from 4D system. I found them a great company to deal with, and who has with some interesting products.

 

[jmumby]

Grrrrr 4dSystems grrrrr

I also have a uDrive. I bought this under the impression that FAT support would 'be supported soon' this was well over twelve months ago. I am slightly bitter about this as the forum keeps being baited with 'coming soon' when they already have fat support for a similar drive on another of there products.

Onboard micro-SD (µSD) memory card adaptor with full FAT16 file support for storing and executing 4DGL programs, files, icons, images, animations, video clips and audio wave files. 64Mb to 2Gig µSD memory cards can be purchased separately.

I have one of the smaller older OLED and these suffer from screen burn very quickly. something to keep in mind if your get one, plays nice with Picaxe.

 

[moxhamj]

I've been very impressed with this little udrive. Haven't played with the oleds so can't comment on those, but the udrive is very simple and it works well with picaxe. I'm slowly working through how CP/M's file allocation system works. CP/M was the precursor to FAT and while it may be a bit more old fashioned, at least it is simple enough to get a grip on how it works in a reasonable amount of time, and none of the source code is "secret". FAT16 is almost retro too. The way CP/M headers are created and blocks organised would be beyond an 08M but may be within the realms of an 18X. File allocation systems are one of those boring "behind the scenes" bits of code that we take for granted, but they mean you can save files and open files etc, and that opens up lots of possibilities. I don't know what the FAT16 code looks like but it would be interesting to see it and see if it can be picaxed.

 

[hippy]

FAT is reasonably complicated, as are most file systems once you go beyond contiguous block files. The biggest challenge is in finding the RAM needed to shuffle bocks around and update data.

For using direct access from a PICAXE and having PC read compatibility, I'd look at formatting the card so it has one big file, then only write within that file area, no need to touch the wrapper file system at all, it's still an X GB or X MB file no matter what's in it. You can implement your own, more simple, file system within that file area if you need to - it's also how Microsoft et al handle virtualisation for file systems and disk-doubling.

That file can then be read on a PC and a PC-side application can extract the data from within it. Having that as a virtual disk driver ( as Microsoft have for disk-doubled files ) would be nice but unlikely.

 

[Marcwolf]

Hi Hippy

Interesting idea for both uDrive/PicAxe and FAT compatibility. Although determining whether the start of file is always in the same place on the SD Card is going to be an interesting issue.

I'll have to look into this. Originally I was just going plug the uDrive into the PC using a USB to Serial unit and write out via that.

The use I plan for it is to hold animatronic sequences and that is just reading the data in using the picaxe.

 

[moxhamj]

Animatronics would be perfect for the udrive, as (I presume) is is just a huge long sequence of instructions. It gets more complex if you are jumping around with different options, eg like a batch file in dos running different programs. But you could still have some simple jumps, eg the udrive could be instruction byte/data byte/instruction byte etc and one type of instruction could be to jump to a different address location depending on the input status of an 08M pin. That doesn't need a FAT or anything complex. Even an 08M could decode it and you can program it as you say from a PC.

 

[Marcwolf]

Hi Dr
Basically that is exactly what I am doing.

First 50 bytes are setup for default servo positions and timings
then 20 x 4 bytes are an index to sequence start points

Then each sequence is read every 250ms. The sequence consists of

1 control byte, and then #servos * (2byte positional, 1 byte speed)

Is the control byte is 0 then it just loads the servo info into an SD21.
If the control byte not 0 then it is a code to either jump to XXXX and repeat Y times, or run sequence Q

All of this can be controlled using a simple RS232 comm and interrupt.

Take Care
Dave

 

[jmumby]

Fat support is supposed to be availabe on this drive. You would get a set of serial commands like mkdir, mkfile or rename and the drive does the rest. No need to reinvent the wheel when it is supposed to be available in the product.

 

[MFB]

The maximum amount of memory that I have used with a PICAXE is 512Kbytes (four x 24FC1025) for a straightforward data logging application. Basically, scan a number of analog and digital inputs at a fixed rate and sequentially write the data to EEPROM until its full, then sequentially down load data to a PC in Excel format. Therefore, no filing system needed.

I recently purchased a uDrive module and plan to substitute it for EEPROM in the same application. Can this be achieved without a filing system?

 

[moxhamj]

Re "Fat support is supposed to be availabe on this drive."

I used this version of the instruction manual http://www.4dsystems.com.au/downloads/micro-DRIVE/uDRIVE-uSD-G1/Docs/Pdf/uDRIVE-uSD-G1_Users_Manual_Rev1.0.pdf Is there an updated one with FAT commands?

The simple system of "send and address, send a byte" is probably more compatable with picaxe than FAT.