RE: [microblaze-uclinux] Minimal mb-system on virtexII

[Kemna Jan-Willem <jan-willem.kemna@thomson.net>]

Ok John,

It is clear that this small pcb isn't going to work.
But... there is another pcb floating around here that has a xc2v3000 on it.
And also Micron DDR-memorie: 4 ic's of 2Meg x 32bit each.
If i try to get two uarts on this v3000-device, then the only thing i need
to 
remove are the gpio's (except for some led's that are also on the pcb).

I assume that i still need to go to Xilinx to get the microblaze-ip, or 
do you have a test version somewhere ??

By the way, when you mention:
> 1 meg absolute minimum to just boot the kernel, 2meg to even think of
doing 
> anything useful.
are you then talking about megabits or megabytes ??

Greetings,
JWK.


> -----Original Message-----
> From: John Williams [mailto:jwilliams@itee.uq.edu.au]
> Sent: Tuesday, September 09, 2003 1:39 PM
> To: microblaze-uclinux@itee.uq.edu.au
> Subject: Re: [microblaze-uclinux] Minimal mb-system on virtexII
> 
> 
> Hi Jan-Willem,
> 
> Kemna Jan-Willem wrote:
> > On my current pcb i use a virtex-II device, currently the 
> xc2v80-4fg256c.
> 
> the v80 might be a bit of a squeeze for any microblaze system 
> - how many 
> slices does it have?
> 
> > The only external component is an AMD-flash memory, 
> currently the am29lv641.
> 
> another difficulty, you definitely need external RAM of some 
> kind, 1 meg 
> absolute minimum to just boot the kernel, 2meg to even think of doing 
> anything useful.
> 
> > The communication with the outside world is now only 
> serially via i2c and
> > spi, 
> > but it should not be too difficult to get a uart connected 
> to it as well.
> 
> I think a breadboard with a couple of wires and a max232 chip 
> would be 
> sufficient for that.
> 
> > I'm wondering if this pcb can be used to start testing with 
> microblaze and
> > uclinux ???
> 
> I'm sorry, from what you've said it doesn't seem likely :(
> 
> > Is the xc2v80 big enough for that or do i have to replace 
> it with a bigger, 
> > pincompatible device (if so, which one, xc2v250 or xc2v1000)??
> 
> again I'm not sure about fitting a mcroblaze system into a 250... the 
> "bare-bones" mbvanilla target uses about 30% of the xc2v1000.  That 
> could be trimmed a bit - see below.  You will have no 
> problems with an 
> xc2v1000... even room left for the xilinx emac core ;-)
> 
> The best bet is to probably grab the mbvanilla_ddr target from the 
> website, and start hacking at the MHS (and UCF) files.  Remove one of 
> the memory controllers, one of the UARTs, and also the GPIO.  That's 
> probably about as small as you can go.  Then synthesise it 
> for different 
> devices and see what it can fit into.
> 
> > What else am i overlooking/forgetting ???
> 
> External ram is a show-stopper.  I think you could _just_ 
> boot uclinux 
> in the internal bram on a xc2v8000!!! not very practical!  for mere 
> mortals like us, the external ram is essential.
> 
> Regards,
> 
> John
> 
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