NEC VR4181A
Hello all,
I need a bit help. First I have to say I am a total newbie in cross-compiler and MIPS-section.
I have a little board with a NEC VR4181A CPU (Mips 64). Now I want to build a kernel for this board.
I think first I have to do is building a Cross-Toolchain, right? Can someone give me some links how to do that?
Then I have to compile the kernel, are there any MIPS-specific things I have to be warned off?
Thanks in advance and many greatings,
Julian
Julian,
We are doing a project here at work with that board. Are you using the NEC Osprey? The board is a POS. Watch out for the voltage buffers on the extern ISA ports not being able to handle the speed of the ISA bus if the board isn't warmed up. Get your heat gun if you're plugging in any hardware to it.
For building your cross compiler (you will want to use mipsel, which is 32. Don't do 64 bit stuff on the 4181. You'll never need it) please see
http://www.ltc.com/~brad/mips/mips-cross-toolchain/ which is a great guide. Take care not to overwrite your PC's libs with mips ones. Ouch. :)
I'm happy with this processor although it is a bit slow. I managed to get worst case interrupt latency at 46 microseconds with linux going full blast on network and compact flash stuff with our external board. (using RTAI and kernel 2.4.18)
Steve
Quoted 26 lines
-----Original Message-----
From: [email protected] [mailto:[email protected]]On Behalf Of Julian Scheel
Sent: Wednesday, February 12, 2003 9:23 AM
To: [email protected]
Subject: NEC VR4181AHello all,
I need a bit help. First I have to say I am a total newbie in cross-compiler
and MIPS-section.
I have a little board with a NEC VR4181A CPU (Mips 64). Now I want to build a
kernel for this board.
I think first I have to do is building a Cross-Toolchain, right? Can someone give me some links how to do that?Then I have to compile the kernel, are there any MIPS-specific things I have
to be warned off?Thanks in advance and many greatings,
Julian
Quoted 4 lines · Steven Seeger
Julian,
We are doing a project here at work with that board. Are you using the NEC Osprey?
Osprey uses Vr4181, which is a different chip from vr4181a.
Quoted 1 line
I'm happy with this processor although it is a bit slow.
Yes, indeed. Pretty the slowest MIPS CPU I ever have dealt.
Quoted 4 lines
I managed to get
worst case interrupt latency at 46 microseconds with linux going full blast on network and compact flash stuff with our external board. (using RTAI and kernel 2.4.18)
Interesting. I was trying to get RT-Linux working at one time but aborted that effort in the middle.
Jun
Quoted 1 line
Osprey uses Vr4181, which is a different chip from vr4181a.
Yeah I didn't notice the A on there. We are looking into the possibility of using the A in our board. Part of the problem is that the A only comes in BGA and we don't like dealing with that.
Quoted 2 lines
Interesting. I was trying to get RT-Linux working at one time but aborted that effort in the middle.
Getting RTAI working wasn't easy. Took over a week and it was supposedly already "ported." One of these days I really must find the time to check in my changes to that project. It works very well and is quite stable. I think 46 us worst-case interrupt response off one of the VR4181's interrupts from an external source is very good.
Steve
Quoted 4 lines · Steven Seeger
Getting RTAI working wasn't easy. Took over a week and it was supposedly already "ported." One of these days I really must find the time to check in my changes to that project.
Or post your patch against linux-mips.org tree somewhere. I am sure more than one people will be interested.
Jun
Quoted 3 lines · Steven Seeger
Quoted 2 lines
Osprey uses Vr4181, which is a different chip from vr4181a.
[snip]
Quoted 9 lines
Quoted 2 lines
Interesting. I was trying to get RT-Linux working at one time but aborted that effort in the middle.
Getting RTAI working wasn't easy. Took over a week and it was supposedly already "ported." One of these days I really must find the time to check in my changes to that project. It works very well and is quite stable. I think 46 us worst-case interrupt response off one of the VR4181's interrupts from an external source is very good.
Hi Steve,
Can you send what you have (or a patch) to Paolo at the rtai mailing list, then he can merge this in with the existing mips stuff that's in there.
Regards, Stuart
Hi,
I'm also suffered from VR4181A :-) I'm now trying to USBFU (device side) driver. The USBFU hardware has many many erratas.
Quoted 3 lines · On Thu, 13 Feb 2003 05:22:36 -0800 [email protected] (Steven Seeger) wrote:
Yeah I didn't notice the A on there. We are looking into the possibility of using the A in our board. Part of the problem is that the A only comes in BGA and we don't like dealing with that.
VR4181 and VR4181A are completely different. A developer of NEC said, "We mistook at naming. The name seems to be upgrade version, in fact, they are quitely different."
On the other hand, VR4122 and VR4131 are similar at hardware level. If you take care of designing board, they can be replaced with others :-)
Thanks.
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Kunihiko IMAI