Options? Need to read off flash card, parse, and send out SPI - What am I up against?

[Andy Baker]

OK - I included that subject line just so you guys wouldn't blow me off as another MP3 player guy asking for somebody to do my work for me.

I'm kinda wondering what I'm up against here. The facts are as follows.

I can program, and I know BASIC well. I've been playing with it for about 20 years now.
I don't know C. Should I learn? Microchip seems to have a hundred different expensive compilers for every chip they make.

I need to get chunks of data off some kind of flash RAM - SD, MMC whatever, that will have been saved in a FAT file system in simple file names or numbers. I have no need to read the names of the files - in fact, I may even be able to refer to them by their starting and ending blocks, or to grab individual parts of one big file - example:

Copy block of 512 bytes from file to RAM, starting at position 52356
Send 512 bytes from RAM out over SPI
Copy the next block of file to RAM, and then send it out too.
Do this a total of 10 times because I want positions 52356-52366

bit rates might be anywhere from 20-30 kbps

Coincidently, the SPI will be going to the newer VLSI MP3 decoder chip - I think it's the VS1012. I have a developer board from Futurlec. Took weeks to arrive from Thailand. I'm not married to this chip, and I'd be thrilled to get suggestions for other solutions. if there are better ones. I just bought this thing on impulse, and now I have an application.

What this all breaks down to is that I need to build a tiny system that is full of a few hundred different pre-recorded sounds that I can call up by number from the PBpro program depending on whatever. I'd like to put the data on an SD, MMC, or other flash device, or even some other kind of non-removable FLASH that I could fill up with a VB program of my own making. Ideally, I could use a computer file system, but something else might be fine too, since I'll know the start and length of all of the sections that I'll need to access.


Suggestions? What am I up against? Should I use pre-packaged FLASH - as in memory sticks? There are licensing fees probably... what about a TQFP 512 meg chip or something like that?

I'd appreciate any insight or direction. Finding useful information quickly is a slow process in this particular subject because of all of the static and noise from people posting "I want to make my own MP3 player - can somebody help"

Thanks!


Andy Baker

[BrianT]

Hi Andy,
I needed a large data storage system to log data off a scientific instrument. I did not care if it was USB, SD, MMC, CF etc but I could not use old faithful RS-232 as those ports are disappearing fast off laptops, plus relying on a laptop or desktop to log the data tied up that computer all day.

I looked at the SD/MMC from CompSys and bought their eval kit for SD/MMC. I also looked at the ALFAT line then decided on the VDIP1 Vinculum from FTDI.

Their eval board is about $US40 and gives you a simple TTL interface to read and write to USB memory sticks. By plugging in a common USB to MMC/SD/Memory Stick/Compact Flash card reader/writer you immediately get access to most of the other card formats.

In its simplest form, the UART mode, the VDIP1 lets you read and write at 9600 bps 8N1 serial ascii over a 4 wire interface. Txd, Rxd, RTS & CTS. By going to a parallel interface the speed goes up to 300 kbps and there are other modes up to at least 4 MBps.

Have a look in Code Examples for the code I wrote to get started.

HTH
Brian

[skimask]

I need to get chunks of data off some kind of flash RAM - SD, MMC whatever, that will have been saved in a FAT file system in simple file names or numbers. I have no need to read the names of the files - in fact, I may even be able to refer to them by their starting and ending blocks, or to grab individual parts of one big file - example:

DOSonChip - plug in an SD card, fire off some serial commands, and you're set.
http://www.sparkfun.com/commerce/pro...oducts_id=7956
Other than that, grab a few datasheets around the 'net and access to an SD card or an Atmel Dataflash chip is a relative piece of cake with PBP.

[Andy Baker]

DOSonChip - plug in an SD card, fire off some serial commands, and you're set.
http://www.sparkfun.com/commerce/pro...oducts_id=7956
Other than that, grab a few datasheets around the 'net and access to an SD card or an Atmel Dataflash chip is a relative piece of cake with PBP.

Hello,

Thanks for the feedback. I looked at the DOSonChip, and it's a great product, no doubt, but way more powerful than I need for this application, plus expensive - at least in production quantities.

I'll keep digging. If I come up with something good, I'll post it.

Anybody used these VLSI MP3 decoder chips with any success?

Regards,

Andy Baker

[Normnet]

See M25P32 PIC Audio
Plays wave files.

Warning: other compiler.
Port to Pic Basic with the new 32 bit variables.

Norm