FSMC external RAM in DMA mode

[fra]

Posted on March 21, 2016 at 01:02

Hello

First to start to develop my new application I need some answers from someone that know FSMC in external RAM mode.

1) Can I consider the external RAM like internal? (using linkerScript.ld??)

2) Is it possibile write in DMA peripheral to memory mode without prebuffer in ''normal'' RAM?

3) And If I have two simultaneous circular DMA pherip-to-mem while I reading some variable under interrupt? The FSMC controller can manage this condition? (multi read/write)

Thanks!!!!!

#external-ram #dma #fsmc

[Tesla DeLorean]

Posted on March 21, 2016 at 01:27

1) Yes, describe it within the 4GB address space, works just like Internal RAM, just a lot slower.

2) You can read/write directly to it, but you have less bandwidth.

3) Access is serialized and arbitrated, just like it is with all the other memory.

I'd recommend reviewing the errata for the specific part in question.

[fra]

Posted on March 21, 2016 at 10:17

Thanks clive for your reply!

Do you have a measure about ''less bandwith''

In your experience with 

http://www.issi.com/WW/pdf/61-64WV51216.pdf

@3.3V (10ns latency) and a STM32L4@80MHz can I obtain 5-10MB/s?