[En-Nut-Discussion] node_cs definition in NUTSPINODE

Jose jose.vallet at aalto.fi
Thu Feb 23 07:44:52 CET 2012


Now that you mention CS lines of SPI drivers, one comment.

A while ago, before the new SPI drivers (in the 4.6 version), we could 
not fully use NutOS SPI drivers in our boards because, to our best 
knowledge, there was not support for decoders in CS lines. That is, we 
wanted 16 chip select lines from up to 4 pins from the microcontroller. 
Thus we had to make our own.

Let me abuse your knowledge here, so I don't have to check the source 
code myself(I' a bit rusty ;)): do the new SPI drivers support decoders 
for the CS lines? If not, it would be a nice feature to have, IMHO.


On 02/22/2012 06:26 PM, Ulrich Prinz wrote:
> Hi!
>> was not a good idea. In practice you will configure Nut/OS for a
>> specific board once and never change it.
> I fully agree :)
>> Furthermore, Nut/OS doesn't currently allow to re-use a device. If you
>> got 4 DataFlash chips, you'll need devSpiAt45d0 to devSpiAt45d3. Each
>> SPI bus device has a fixed hardware chip select.
> Right, there must be one ICB per used ChipSelect even the SPI bus
> itself is reused.
>>> In that light I propose
>>> to make node_cs a 32 bits entitie.
>> My proposal would be to remove the cs parameter and configure the chip
>> select in the device driver.
> I fully agree, as it is more convenient to do hardware-configuration
> by qnutconf instead doing some here, some there, some...
>> I'm open to arguments, of course.
> Here you got mine :)
> Ulrich
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