[hpsdr] Operating Configurations

[Philip Covington]

Hi Lyle,

<snip>

> >
> > 3. SPI EEPROMS would not be practical since they each need a CS line
> > and we only have 5 defined on the bus.
> >
> > If there is a EPM240 (or FPGA) on the slave boards that is standing
> > between the board and the ATLAS bus (like the one in JANUS), we might
> > be able to do a little trickery with the SPI bus by defining some
> > simple addressing protocol that the EPM240 decodes.  That way we could
> > have multiple SPI devices on a board but still use the ATLAS nCS(0:4)
> > chip select lines from the OZY.  By writing to a register in the
> > EPM240 we would select which SPI device on the board that is being
> > addressed/connected to the ATLAS SPI bus.  One particular address
> > would be reserved  for reading/writing the EPM240 user flash memory
> > with the board's configuration settings/ID.  Since we know that
> > address and we know which nCS we are asserting, then the FX2 could
> > read the board configs on start up as in the 1-Wire case above.
>
> If it is an FPGA, though, that needs to be configured by Ozy first,
> we're back to square one :-(
>
> 73,
>
> Lyle KK7P

I guess I envisioned that the "other" FPGAs would have a configuration
device to start it up... ;-)  I am not sure I would want to always
download all device configurations over USB to the FPGAs on the slave
boards.  Still, I concede it is a problem since we want the config
data to be in something that will always be there regardless of type
of device or whether it has has its brains uploaded.

Well, I am going to add the 1-Wire bus anyhow...

73 de Phil N8VB

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