Do I have to use a ARM MCU with EMI to use external flash and DRAM?

can AT91SAM7X256 have external flash and DRAM? AT91SAM7X256doesn't have
EMI(external memory interface) , is it possible to extend external
flash and DRAM? thanks

-- 

"jetq88" <jetq5188@gmail.com> wrote in message 
news:1159375445.766281.212270@h48g2000cwc.googlegroups.com...
> can AT91SAM7X256 have external flash and DRAM? AT91SAM7X256doesn't have
> EMI(external memory interface) , is it possible to extend external
> flash and DRAM? thanks

The SAM7X does not have an external data bus or address bus as far as I am 
aware so your only options are serial devices for a little more flash, or a 
very slow bit banged interface though an IO port.  Neither of these are any 
good for executing code.  I believe there is an equivalent part that has an 
external bus - why not use that?

Regards,
Richard.

+ http://www.FreeRTOS.org
+ http://www.SafeRTOS.com
for Cortex-M3, ARM7, ARM9, HCS12, H8S, MSP430
Microblaze, Coldfire, AVR, x86, 8051 & PIC18 * * * * 

hi, Richard,

thanks for your answer, I have another question for you,
if I use AT91SAM7x256 with your RTOS from freeRTOS.org, what size of
footprint is it?
do I still have room to grow if I add TCP/IP stack and/or USB
host/device later on?

thanks

FreeRTOS.org wrote:
> --
>
> "jetq88" <jetq5188@gmail.com> wrote in message
> news:1159375445.766281.212270@h48g2000cwc.googlegroups.com...
> > can AT91SAM7X256 have external flash and DRAM? AT91SAM7X256doesn't have
> > EMI(external memory interface) , is it possible to extend external
> > flash and DRAM? thanks
>
> The SAM7X does not have an external data bus or address bus as far as I am
> aware so your only options are serial devices for a little more flash, or a
> very slow bit banged interface though an IO port.  Neither of these are any
> good for executing code.  I believe there is an equivalent part that has an
> external bus - why not use that?
>
> Regards,
> Richard.
>
> + http://www.FreeRTOS.org
> + http://www.SafeRTOS.com
> for Cortex-M3, ARM7, ARM9, HCS12, H8S, MSP430
> Microblaze, Coldfire, AVR, x86, 8051 & PIC18 * * * *

jetq88 wrote:
> can AT91SAM7X256 have external flash and DRAM? AT91SAM7X256doesn't
> have EMI(external memory interface) , is it possible to extend
> external flash and DRAM? thanks

If you need external flash and SDRAM, you'd be better off with the 
AT91SAM9260.
(Unless you really need the integrated CAN controller)


-- 
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 

> hi, Richard,
>
> thanks for your answer, I have another question for you,
> if I use AT91SAM7x256 with your RTOS from freeRTOS.org, what size of
> footprint is it?
> do I still have room to grow if I add TCP/IP stack and/or USB
> host/device later on?
>
> thanks

Take a look at the FAQ - info is provided for ARM builds.  I have used the 
SAM7X256 with uIP and lwIP, both with a simple USB driver included in the 
build so I don't think size is an issue.


Regards,
Richard.

+ http://www.FreeRTOS.org
+ http://www.SafeRTOS.com
for Cortex-M3, ARM7, ARM9, HCS12, H8S, MSP430
Microblaze, Coldfire, AVR, x86, 8051 & PIC18 * * * *