From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 23 Jul 2003 10:07:22 +1200 From: Robin Gilks Subject: Re: Clock rate on MPC8xx CPUs In-reply-to: <3F1B4BA1.6000204@tait.co.nz> To: linuxppc mail list Message-id: <3F1DB59A.60603@tait.co.nz> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii; format=flowed References: <3F1B4BA1.6000204@tait.co.nz> Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Robin Gilks wrote: > > Greetings > > Can anyone shed some light on a question of clock rates? > > We're playing with the mpc866ads board and currently running both the > CPU core and bus at 50MHz to keep things simple. As a result it seems > that the internal Linux time is 50% out despite passing the clock rate > from u-boot as being 50MHz. > > Since the mpc866 can run its core at x2 the bus rate, does the timer > setup in Linux for this port assume that the CPU _will_ be running at x2 > from the rate passed at boot time or is there something else > 'interesting' with this new '866 CPU :-)) Further questions on the same subject... Does anyone have a utility that will report the CPU clock rate - we have confirmed that the bus is running at 50MHz and that the timers are accurate (so must also be running from the 50MHZ external bus) - but we still have no definitive value for the clock rate of the CPU core... -- Robin Gilks Senior Design Engineer Phone: (+64)(3) 357 1569 Tait Electronics Fax : (+64)(3) 359 4632 PO Box 1645 Christchurch Email : robin.gilks@tait.co.nz New Zealand ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/