Does anyone know of any serial interfaced (RX/TX) 1Mb-ish, (or larger) flash ram storage systems for micros? Needs a simple file like indexed system, so data chunks can be written, retreived, and deleted. Much like a hard drive system.
I know a USB ram drive will do this, but I would like something to interface easily to any micro with a uart.
Thanks in advance, Don...
Don McKenzie E-Mail Contact Page:
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Crystal clear, super bright OLED LCD (128x128) for your microcontroller. Simple serial RX/TX interface. Many memory sizes.
Serial Data Flash from ATMEL ( and others ) have this, tho it is SPI.
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This is a block orintated device.
A hard drive is block based and buss based flash chips are linear.
A block based device (hard drive or Flash Cards ) have some sort of file system such as FAT16 / FAT32 or others that don't seem to mater much.
So, I don't understand your question ??
USB drives are always FLASH based, I have never heard of a USB _ram_ drive.
This is one I have done some research on :
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but I have not used it.
I found is their docs that it apears kind of slow. The max data rate is less then 1M Bit serial. Then there is the programming time. Only one file open at a time.
I used a ATmega32 and a compact flash card and approched 4 MBytes/sec transfer rate for 512 byte blocks.
This was only a read/write test, so I did not have any file system code.
As per normal, my initial question may not have explained fully what it was I was chasing, but two very good leads. The Rogue Robotics device seems close to my needs.
Don...
Don McKenzie E-Mail Contact Page:
formatting link
Crystal clear, super bright OLED LCD (128x128) for your microcontroller. Simple serial RX/TX interface. Many memory sizes.
You might want to consider the AT45DBxxx series of dataflash. This has an SPI interface and SMALL sectors (up to 1 kB). The advantage of small sectors is that file system typically do not need garbage collection (or it is simplified). The pages have "extra bytes" allowing erase count and other things useable in a flash file system. The devices start at 1 Mbit and go up to 64 Mbit in pin compatible 8 pin packages. Larger memories are in development.
You can also get 16/34/64 Mbit in MMC like Flash card packages, so add an MMC connector to your board and you are in good shape.
I've used the Atmel DataFlash memories that Ulf Samuelsson recommended and found them easy to program (important) and also easy to wire to my microcontroller (really important for me, probably less so for you). I used the Atmel AVR microcontroller's built in SPI interface, but the implementation is restricted to the basic SPI operations and shouldn't be too hard to do "in code". In either case, the interface requires 4 i/o pins. As I recall, the maximum data-clock rate for the DataFlash units was about 7 or 8 MHz, but I used an old chip. Atmel also likes to talk about low power consumption, though that never factored in to my particular implementation.
This chip is also available on a finished product, with Flash card electronics, holder, etc., at Sparkfun.com. About half the cost of the Chipdos dev board, but also without the RS232 (TTL serial only).
It is now for me too, so it's not just your routing. Got me concerned because we (Sparkfun and Budget Robotics) use the same Web host provider. Or at least we used to. My site is still up, and there's comes and goes. Might just be their box.
Yes, they do good work. And it's generally inexpensive. We need more good, inexpensive stuff!
Unfortunately, their MP3 breakout board is currently out of stock, but the DOSonChip and MP3 board would make a good pair for playing sound/music/effects on a bot. OTOH, the price together is a bit high. They also do a VS1002 MP3/SD module, and the Rogue Robotics uMP3 board is a good option for those going in that direction. Choices, choices...
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