Re: [ts-7000] Re: Standard SPI vs. 3 wire SPI

[Razvan-Ionut Stoian <>]

I read some forum threads and converting from 4 to 3-wire SPI seems trivial on AVRs. They tied MOSI and MISO together and used a 100k  pull-up. They then sent a command (any command) to the slave and clocked an answer from the ADC to the master.

I tried to do the same, but all I got was what I posted in this thread earlier. 

--- On Sat, 12/11/10, Jason Stahls <> wrote:

From: Jason Stahls <>
Subject: Re: [ts-7000] Re: Standard SPI vs. 3 wire SPI
To:
Date: Saturday, December 11, 2010, 8:34 PM

 

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 12/11/10 19:59, Razvan-Ionut Stoian wrote:
> I have implemented lots of 3 wire ADC designes using bitbanging. I know that whenever CS goes low, one can clock slave's output out to the SBC's GPIOs. It seems that using four wire interfaces to get data out of 3 wire devices is not a trivial task, after all.
>
> It's a bit frustrating, since the SPI interface on my ATmel board is extremely fast (133MHz/[1-255]) and doesn't work the CPU as much as the GPIOs. So the advantage of using this over bitbanging is obvious.

I'm somewhat suprised, most Atmel AVR uC's have the ability to run a
3-wire SPI... I would have thought that their larger 32bit stuff would
do the same.

- --
Jason Stahls
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.16 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/

iQEcBAEBAgAGBQJNBCa1AAoJEBWmhVAMrS/gvecH/1GpRxYNBSdAuDw6E+R+4sWA
bwwZl0P7w1BI0AKh+l2JdjTcXBvLtUJXEMgGLrTAqif39cOPlVjfTIyEjvmXjfOz
hwZaU8hsq6ZNQmLhmcP5+95/RmNZrcPMxbzdvFiqaONWG9xaYP9uvIHXwRdmjhzO
PZ/vYxXEBQ8cywwsRBSN5Ekr5Y2GMdheezeZhTo4008BZP/S2vL2yqlZ39nDmupZ
kqFmQwtooa9EpFEGT2puehpbSTPt9SHy6+m4xZQ/kHntXHj7pIF92doEmQf0nfHk
PRRS7l8EFev+XZ7w1ltU7jK5LIwZNl6AI6wEwtjCQ3ImamcU3lRT/qJfWfqb/9o=
=UlG5
-----END PGP SIGNATURE-----

__._,_.___

Your email settings: Individual Email|Traditional
Change settings via the Web (Yahoo! ID required)
Change settings via email: =Email Delivery: Digest | m("yahoogroups.com?subject","ts-7000-fullfeatured");=Change Delivery Format: Fully Featured">Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | =Unsubscribe

__,_._,___