Hi,

most of the demo stuff for vhdl is designed for 16-bit

the steps you would have to take to make the whole thing 8-bit would be 
1.) adapt vhdl-foxbone code
2.) kernel drivers (linux-2.6/drivers/fox-vhdl/foxbone*)

i can give you advise with the kernel side, for the vhdl stuff, you
are probably best of asking roberto.

the other thing is, that the 8-bit that you do not want to use, would
have to be put into input on the fpga.

however, you are aware, that there is a vhdl module, that lets you use
the fpgas pins as gpio ?  this will be slower than std gpio though..

what application are you trying to make ?

John

--- In [email protected], "andrea.maccaferri"
<[EMAIL PROTECTED]> wrote:
>
> I'm just waiting for a FOX VHDL dev kit to do some test,
> meantime I just wonder me if it will be possible to implement
> a reduced FOXBONE protocol version, enabling use of only 8 bit bus,
> this could help in application where I/O have to be saved.
> 256 register may be enought for many applications, the same for
> register size.
> I know that you have designed it to assign different address to
> different function, so a reduced addressing schema could be a problem,
> but this could be resolved writing address in 2 phase, first 8 bit
> at address_write rising edge and second 8 bit of address at falling 
> edge.
> 
> The main problem that I see at the moment is foxbone release 
> version number that actually is described by 16 bit.
> 
> Let me know what do you think about and if anybody else has the same
> requirement.
> 
> Andrea
>


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