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Message
From: Jeremy Bennett<jeremy.bennett@e...>
Date: Wed Sep 3 10:54:16 CEST 2008
Subject: [openrisc] Re: OR1K in FPGA
On Tue, 2008-09-02 at 16:41 -0300, Felipe wrote:
> Hi Jeremy!!!!
>
> I am using a XUP Virtex-II Pro of Digilent, it has a usb jtag config
> connection and a Parallel Cable IV connection.
>
> Other problem is the memory interface, in the hardware tutorial of the
> opencores site, the memory interface is removed, and a small memory is
> assigned.
> Now I want to pass the linux image for the openrisc, and I'll need of
> the memory interface, but in the XUP Virtex-II Pro the memory is
> SDRAM, and in the or1k the interface is for a SRAM memory........
> I am using the Xilinx ISE software, and the UCF pins of XUP Virtex-II
> are different of the Or1k memory interface pins.
Hi Felipe,
I've copied your message and my reply to the OpenRISC mailing list, so
the whole community can benefit from the dialog and contribute.
I'm primarily a software engineer, but if you want to use the Digilent
memory, then it looks like you'll need to design a SDRAM interface in
Verilog. From memory the OR1K Verilog has support for various different
types of memory, so there may be something you can base it on. If you
write it up, that would provide a very helpful modern tutorial on OR1K
hardware.
The ORSoC guys sell a USB JTAG interface for OR1K, which works with GDB.
You'll need to write the server side of the OpenRISC 1000 Remote JTAG
interface to drive the Diligent version. That would be something you
could contribute back to the OpenCores community. I suggest you use the
code in Or1ksim (look in the debug sub-directory) as the basis of this.
The alternative is to use the GDB Remote Serial Protocol. It is just
possible the Digilent guys already have a GDB RSP server for their USB
connection. You will need to modify it, so it understands that it is
talking to an OpenRISC. Then you should be able to hook up from OR1K GDB
with
target remote ...
I've recently written up my experience of porting GDB to OpenRISC as a
"HOWTO". That may give you some insight into the software side of things
- particularly how the JTAG debug interface works.
http://www.embecosm.com/download/ean3.html
I hope this helps.
ATB,
Jeremy
--
Tel: +44 (1202) 416955
Cell: +44 (7970) 676050
SkypeID: jeremybennett
Email: jeremy.bennett@e...
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