cvs commit: src/sys/arm/at91 at91_spi.c at91_spiio.h at91_spireg.h

[Daniel O'Connor]

On Saturday 15 July 2006 07:23, M. Warner Losh wrote:
> SPI == Serial Peripheral Interface.  It is common in the embedded
> world.  The 'bus' is nothing more than 4 signals: chip select, clock,
> MOSI (master out, slave in) and MISO (master in, slave out).  Lots of

It's not even a bus, only a point to point interface.

> cool things live on the spi bus, but I'll just be committing support
> for AT45 DataFlash parts.  The framework is general enough to support
> other things.  In one of the hardware hacking lists I'm on, people
> were talking about writing a driver for a SPI Ethernet whatsit, but
> I'm unsure how that works, since there's no interrupt signal on this
> bus...

You can poll it (the Microchip ENC28J60 anyway) or assign a GPIO pin as an 
interrupt line.

There is a TCP stack for the various 16 bit micro that can use it.
http://www.sics.se/~adam/uip/

Another interesting SPI part is the Maxim MAX3420E - it is a USB slave 
interface. http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4751

(As you might have guessed I am looking at using these parts, although with a 
16 bit AVR, not this fancy ARM stuff :)

Another way to use the SPI would be to connect a microcontroller and slave it 
to the ARM for whatever thing you might need that isn't already built into 
it..

-- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/cvs-src/attachments/20060715/9ed0bf06/attachment.pgp