Re: [Socketcan-users] Fwd: sja1000 BasicCAN mode

[Kurt Van Dijck <kurt.van.dijck@eia.be>]

On Thu, Nov 17, 2011 at 05:24:17PM +0100, Oliver Hartkopp wrote:
> On 17.11.2011 17:11, Kurt Van Dijck wrote:
> 
> > On Thu, Nov 17, 2011 at 07:58:09PM +0400, Yuriy Kiselev wrote:
> >> 2011/11/15 Heinz-Jürgen Oertel <oe@port.de>
> >>
> >> Yes, BasicCAN mode is for specific designed devices. My device has only
> >> 5-bits address bus and I can't use PeliCAN mode.
> > Still, properly attached SJA1000 is better used in PELICAN mode. I'm sure
> > you agree.
> > 
> > But I see your point.
> > Must your hardware be supported by SJA1000?
> > Or by a completely seperate 82c200 driver?
> > You probably can start from the SJA1000.
> 
> 
> AFAIK the SJA1000 driver only uses 32 byte of address space - so 5 bit are ok!
> 
> Even if the address space of the SJA1000 can be 128 bytes in PeliCAN mode,
> these addresses beyond register 31 are usually not in use.
> Registers 32 - 127 only contain a view into the internal registers and FIFOs
> nobody is using, as the FIFO is also implemented in the standard RX/TX frame
> registers.
> 
> Please check the SJA1000 spec, page 21/22 (PeliCAN address space layout)

Not having checked the number 32, you're completely right in that the upper part
of the register map is never accessed.

Regards,
Kurt