Flash Interface with AT91RM9200

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Hi,
  I am doing a prototype baord based on AT91RM9200.I am planning to use
Intel Strataflash memory (E28F640J3A)on the board.This flash memory i
having a program enable input.How can i connect this to the processor
while interfacing?If anyone is using the same flash, please suggest.
  Also I would like to understand how does the USB_DP_PUP signa
enable/disable the pull-up resistor on DP?(Ref: Interfacing USB Devic
peripheral-AT91RM9200 datasheet)
Best regards,
S Mahesh.


Re: Flash Interface with AT91RM9200
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The VPEN pin is used to lock/unlock the device globally for writing. If
you wish to have some certainty that the device may not be written to
in a spurious manner (during startup/shutdown, for example), connect
this pin (with a pulldown of about 100k) to an IO port bit. The
pulldown will ensure VPEN is invalid until the processor starts up and
initialises the port bit, preventing spurious writes. If you believe
there should be no problem, pull the line to Vdd through 100k. This
will make the device unlocked (at that level, anyway) at all times.
Note you still have to write to the device to unlock blocks.

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The USB spec can clear this up. An upstream (slave) port has to signal
it is present. It does this by pulling the DP line high through 1.5k,
1%. Releasing this line permits the downstream (host) to pull *both*
lines low (through 15k). With both lines low, no active device is
assumed to be attached.

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Cheers

PeteS


Re: Flash Interface with AT91RM9200
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use
Hi
  Thanks for the suggestion. If we are using a single flash memory IC, i
it possible to have a glueless connection? in that case, can we connec
the chip select signal from controller directly to CE0 (with CE1 and CE
connected to GND)?
Regards,
S Mahesh.



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