Ben and Ethernet

Werner Almesberger werner at
Tue Aug 31 08:45:07 EDT 2010

Rikard Lindstr?m wrote:
> i was thinking of etching a 0.8mm thick PCB (single
> sided) that fits in the microSD-slot and continues outside,

That's actually a nice idea for making extensions. More friendly than
having to wire everything to TPs.

One limitation seems to be that you couldn't do hardware-accelerated
SPI. (The MMC/SD controller supports MMC bus widths of 1 and 4 bits,
but I don't see a "downgrade to SPI" option with separate data lines
for input and output.)

But you'd still have bit-banging GPIO.

Suggestion: design a very simple boards with a bunch of LEDs or such
to demo the concept. Then anyone else can build their stuff upon a
proven design, with proven design files.

- Werner

More information about the discussion mailing list