ben-wpan: commercial description

Werner Almesberger werner at
Tue Jun 7 16:56:48 EDT 2011

David Kuehling wrote:
> just wondering about that paragraph: you mean the atben does not
> implement SDIO?  So what protocol are they talking?  Sounds like you
> imply it does bitbanging.

Yes, that's correct. The transceiver needs full SPI (4 signals) plus
2-3 control signals (reset, interrupt, a multifunctional pin called
SLP_TR). In the case of atben, we cheat a little and do only power-on
reset, saving the 7th pin.

Since there's no "pure" SPI available on the pins of the 4720's MMC
controller (alas, it doesn't implement MMC SPI mode), the way to go
is bit-banging. The maximum over-the-air bit rate is 2 Mbps, so
bit-banging is sufficiently fast, if a little CPU-hungry.

- Werner

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