OPENCORES.ORG

From: Jeremy Bennett<jeremy.bennett@e...>
Date: Thu Aug 21 09:29:06 CEST 2008
Subject: [openrisc] Re: OR1K in FPGA

On Tue, 8/19/08, Felipe Henes <fhenes@g...> wrote: > > I am trying to pass a linux image to the OpenRisc running in a Xilinx > VirtexII-PRO FPGA, could you help me to do it?????? > > I have the system image running in the simulator and the processor > running in the FPGA, but I don't know how to download the system to > run in the processor.... > > Can you help me??? > > Hi Felipe, I've transferred your question to the OpenRISC mailing list, so the wider community can participate and benefit. There are some short papers on building OpenRISC on FPGA written by Patrick Pelgrims, Dries Driessens and Tom Tierens of the De Nayer Instituut at the Hogeschool voor WetenSchap & Kunts in Belgium. The hardware tutorial can be found on the OR1200 page (http://www.opencores.org/projects.cgi/web/or1k/openrisc_1200) and the software tutorial on the OpenRISC 1000 toolchain page (http://www.opencores.org/projects.cgi/web/or1k/gnu_toolchain_port). This is now rather old. The hardware guide will probably help, but it sounds like you already have the hardware running. The key is the software. This uses GDB to download and run the software on the FPGA. However the software paper describes the old GDB 5.0 port for OpenRISC, which is nearly 10 years old. Since then both OpenRISC and its JTAG interface have evolved. In particular there are two flavours of the JTAG interface. The older version is included in the ORPSoC RTL tree, the newer version (by Igor Bodor) is a separate OpenCores download. The newer version is simpler (i.e smaller) and has a slightly different scan chain for CPU control. The OpenRISC has also evolved, with different structure to its configuration registers. I have recently ported GDB 6.8 to OpenRISC 1000, and considerably simplified the code. You should use this to interface to your FPGA and download software. http://www.embecosm.com/download.html The key is to understand your JTAG interface. How are you physically connecting your workstation? Is it a direct connection, and if so what sort of connection? The GDB 6.8 port includes code for direct connection via the parallel port to a JP1 header and for remote connection via TCP/IP. The remote connection is also used for newer hardware connections (e.g. USB connections). A small program acts as the server side of the TCP/IP connection and drives the actual hardware interface (e.g. USB) - this program will be different for each type of hardware interface. ORSoC (http://www.orsoc.com/), the owners of www.opencores.org, make and sell such a USB JTAG debugger interface). If you let us know details of your connection, I'll advise further on how to get GDB 6.8 connected, so you can download, run and debug your software. ATB, Jeremy -- Tel: +44 (1202) 416955 Cell: +44 (7970) 676050 SkypeID: jeremybennett Email: jeremy.bennett@e... Web: www.embecosm.com