On Fri, Jan 31, 2014 at 11:49 AM, Dr. H. Nikolaus Schaller hns@goldelico.com wrote:
...
Options to solve this are
- replace the eMMC by the Micro-SD (which will have a much lower speed
limit!)
- interface WLAN though SPI (is not optimal for 802.11n) and use the SDIO3
port
- interface WLAN through (internal) HS-USB (likely to draw more power and
needs different chipset/module) and use the SDIO3 port
- interface the Micro-SD slot (or even the second full speed) slot though
USB (needs a probably power hungry SD-USB controller chip like [1])
Both eMMC and internal SD would be a bit overkill IMO, so we probably should choose one of them. The forum posters claim there is not much speed difference but I'm not sure if it's really so in practice, as eMMC has 8 data lines and SD only has 4 and not all MMC interfaces support high speed clocks.
About using SPI, the Jorjin modules ED inquired about don't seem to have SPI mode any more, so probably different modules would be needed (unless Jorjin can offer SPI versions of the same modules).
Another thing that needs to be checked is if pin mux options allow the whatever configuration we want, as lots of things share pins and some peripheral we want to use may use up some pins and make another peripheral unavailable.
GraÅžvydas