Re: 66 Mhz bus clock for EST8260?

[Jerry Van Baren <vanbaren_gerald@si.com>]

Yes, that is what we did and it worked, including running linux, as I
recall.

We have not run extensively with the 66MHz bus clock.  Our processor
was 166/133/66 rev A.1 so we clocked the processor at 166MHz (MODCK_H =
0101, MODCK[1-3] = 110).  We played with overclocking the CPU: we were
able to run quite a bit faster than 166MHz at the 33MHz bus speed
(300MHz?), but died right away when we tried to overclock with the
66MHz bus speed.

For more details, I would have to dig out some notes.

gvb


At 12:47 PM 12/8/00 -0600, Brian Ford wrote:

>Is there any magic in getting the EST8260 board to work with a 66 Mhz bus
>clock?  I haven't had good luck with a Linux or vxWorks image.
>
>My board has a 200/166/66 rev A.1 chip.
>
>I boot using a vxWorks bootrom.  I have made a few corrections to the
>bootrom so the decrementer frequency is set correctly from the user
>dip switches in addition to setting the core, cpm, and bus speeds.
>
>The scenerio is as follows:
>
>1.) Burn configuration word to change MODCK_H from 0x0001 to 0x0101
>2.) Swap oscillators 33.0 -> 66.0 Mhz
>3.) Set MODCK[1-3] switches to 0x111 (200/133/66)
>4.) Mirror 3.) on user switches for vxWorks bootrom to read
>5.) Hack head_8260.S to put immr in place for Linux
>6.) Set linux board info in embed_config.c to 200/133/66/66
>(core,cpm,bus,brg) making sure there is real space allocated for it
>instead or whatever was in r3 when vxWorks booted us.
>6.) Reboot.
>
>vxWorks bootrom runs fine and downloads Linux or vxWorks.
>
>Linux pannics just before giving me a shell prompt somewhere in tty init.
>
>vxWorks appears to come up fine, but the muxDevBind fails for the Fast
>Ethernet and thus no network communications.  Even though the bootrom
>just downloaded us successfully over the same interface.
>
>Has anyone had any luck with the 66 Mhz bus clock?
>
>--
>Brian Ford
>Software Engineer
>Vital Visual Simulation Systems
>FlightSafety International
>Phone: 314-551-8460
>Fax:   314-551-8444
>
>


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/