Re: AT91rm9200 Devel. Board (Student Project): Choice of OS??

From: Ulf Samuelsson (ulf_at_a-t-m-e-l.com)
Date: 02/11/05 

Date: Fri, 11 Feb 2005 17:01:50 +0100

>
> EBV is supporting my project and supplies AT91RM9200 QFP samples...
> so probably PCB design will be finished by next week:
> - 100 * 160mm2
> - AT91RM9200-QI-002
> - 64MB SDRAM
> - 8MB flash
> - CF slot
> - USB A/B
> - Ethernet
> - RS232/JTAG
>
> Nothing fancy though (o;
>
> rick

Nice, did you get any dataflash from them?
Soon there will be 128 Mbit dataflashes avaialble in SO-8 pinout.
Some issues:

The AT91RM9200DK CF interface has a bug.
There is an FAQ on the subject on the atmel Website.

If you uses buffers on the board, then again, you need to beware of a
another bug in the DK.
SDRAMCS (inverted) cannot be used as the buffer enable, since the chipselect
becomes active during refresh.

You have to reset the JTAG and the CPU reswet, otherwise it will fail.
It is not good enouigh to pullup the JTAG reset,.

If you do want to use the dataflash, then you need to consider how to do
failsafe operation if the programming of the flash fails.
This can be as easy as a jumper on the dataflash chipselect
or an OR gate qualifying the chipselect.
The other input is pulled low by a resistor, but can be pulled high by a
jumper to disable the access
forcing the AT91 to download from UART/USB.

If you want to use the USB, yuou may have to use the 18,432 signal the DK is
using.

I can have a look at the schematic, if you are interested.
In that case, mail me directly. 

--
Best Regards,
Ulf Samuelsson
ulf@a-t-m-e-l.com
This message is intended to be my own personal view and it
may or may not be shared by my employer Atmel Nordic AB