Flash drive

[Dr_Doggy]

what am i looking at is to interface (hardware level) with usb thumb drive, without a computer, obviously one wire is data in, and one is data out,

I am mostly interested in the basic functions, how to access a specific memory block, save a bit(or byte), and read that bit(byte)

im obviously looking at serial data, is it 8 bit + parity?


cant use micro-controllers, I am going to import the data parallel using simple switches, then convert it to serial to input to the drive,

a good example is a circuit that can go through the drive blocks, write some 1's, then go back through and read back those 1's, maybe with a counter or 2to see how many ones it read/wrote.

any help would be great, even what this code type is called could help, so far i can't find anything on accessing these things.

also i may want to hack the clock to make it run on external(to slow it down)

 

[Nigel Goodwin]

You're not going to access it in that way, you need a USB host, which means a processor - and not even many microcontrollers will do USB host mode.

 

[Dr_Doggy]

is that how the new tv's and car radio's are doing it?

For my application i am not interested in file systems or anything, just individual blocks, but i'd like a meg or gig available, maybe there is something better i can use?

maybe a chip where i could input a hex command to access the block, then a read/write function for it, is there an IC like this or maybe I should use a SD card or maybe something better is out there?

 

[tcmtech]

one meg with simple switches?

Lets say you can do 1 switch flip a second for 1 million seconds, 1000000/3600 or 277.77 hours.

1 Gig will be a thousand times that or around 31.7 years if you never stop for sleep or dinner!

I am sensing a scaling of practicality issue here.

 

[Atheist]

Depending on your application, I believe it would be much, much easier to do this using an SD card.

The data within an SD card can stored using a FAT file system or can be written as raw data to 512B sectors. My best advice on accessing this information, which again may not be possible depending on your application, would be to use a microcontroller configured as SPI master and communicate with the microcontroller SD card configured as SPI slave. I have a setup similar to this sitting not a foot from my laptop as we speak. An SD card socket can be purchased from Sparkfun or other vendors. Sparkfun also sell the socket on a break out board which, although considerably more expensive, is certainly very useful in prototyping.

Please post more about your application if you would like more focused help.

 

[Dr_Doggy]

i was thinking of spoofing the access command with a parallel to serial register, use a bcd counter parallel to serial to set up the hex address, then use an signal from a controlled op amp to send in the bits.

iv been reading along the lines of EEprom so far it sounds best, would that be easier than SD?

the EEPROM I am looking for would preferably be:

serial 1bit data in
parallel hex address map
separate data in /out wires
simple read write switching
burst mode
I am liking the parallel ones so far but i can't find one with separate data I/O pins
any suggestions?


i just have one question, what is the diff between I^2C and Microwire?

 

[Nigel Goodwin]

is that how the new tv's and car radio's are doing it?

Of course.

 

[Sceadwian]

You are never going to be able to manually access a USB device, look up the USB specs and the requirements for host and device communication and handshaking (called enumeration) and you'll see why, USB has nothing whatsoever to do with standard serial communication protocols, aside from the fact that the data is still transmitted serially, the protocol itself is complex and multi layered.


Try a Viniculum module, it can act as a USB host that will interface with USB storage class devices and allow the block access you want via a serial command set on logic level I/O pins so you can interface it with a micro controller, they have modules that have built in micro controllers as well so once you learn to reprogram the firmware you can do what you want.

If using an external module such as the Viniculum, or micro controllers is explicitly prohibited there is no way you can do what you want.