Intro and some questions

NeonJohn jgd at neon-john.com
Sat Feb 23 11:38:06 EST 2013



On 02/20/2013 09:51 PM, anish singh wrote:

>> I intend to embed the BB in our new product if I can solve a small
>> problem.  The BB has 2 SPI ports, 1 with 1 chip select and the other
>> with 2.  Only one port is supported in the standard kernel.  I found
>> some info that guided me into activating the new port and having all
>> three devices enumerated in /dev.

> Which three devices?

Not that it matters but a 1 MS/S A/D converter, a DDS synthesizer and a
bit of an FPGA that fans out one word of data to 16 control lines.

>>
>> What I have not yet been able to do is figure out how to enable that
>> second chip select line.  So my first question is, where do I start

> What does this second chip select line does?

Pick one of the three functions above.

>> looking for the existing code?  I'm hoping that I'll be lucky enough to
>> reuse that code, changing a bit or two in the CPU register.

> Can you show us the schematic?

No, it's still just a pencil sketch.  But I don't need a completed
schematic to know that I need 3 SPI channels and the Bone only has one
enabled by default.  I've enabled the other port.  Now I need to figure
out how to enable that port's second chip select line.  That was my
question.  Any suggestions?

John


-- 
John DeArmond
Tellico Plains, Occupied TN
http://www.fluxeon.com      <-- THE source for induction heaters
http://www.neon-john.com    <-- email from here
http://www.johndearmond.com <-- Best damned Blog on the net
PGP key: wwwkeys.pgp.net: BCB68D77



More information about the Kernelnewbies mailing list