From mboxrd@z Thu Jan 1 00:00:00 1970 To: linuxppc-embedded@lists.linuxppc.org Subject: Re: Serial console ports on systems with no console connected. In-Reply-To: Message from Arun Dharankar of "Tue, 09 Jul 2002 19:45:19 -0400." <200207091945.19620.ADharankar@ATTBI.Com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 10 Jul 2002 16:47:28 +1000 Message-ID: <2088.1026283648@msa.cmst.csiro.au> From: Murray Jensen Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: On Tue, 9 Jul 2002 19:45:19 -0400, Arun Dharankar writes: >Also have the serial port speed set at 115200, I >dont believe this is buffer overrun issue. If you want to go faster than about than about 38400, you need to get a different clock source for your baud rate generators (Tom Rini has a patch from me to add support for an external clock source for BRGs on the 8260 in linuxppc_2_4_devel). By default, the SCCs and SMCs use a clock source that won't divide cleanly at the higher baud rates - the error becomes so large that it simply stops working - which is what you are getting by the looks of it. Try running the serial ports at 19200 and see if that works. Cheers! Murray... PS: the patch Tom has is trivial - you still need to hack the 8260 uart driver to use the new code (also trivial), plus your hardware needs an external clock source (distinctly non-trivial if your board design doesn't include one already - our hymod board has a 3686400Hz clock source wired appropriately, which allows up to 230400bps if you use 16x oversampling) PPS: ppcboot already has support for external BRG clock sources - see include/config_hymod.h for an example of how to configure it. -- Murray Jensen, CSIRO Manufacturing Sci & Tech, Phone: +61 3 9662 7763 Locked Bag No. 9, Preston, Vic, 3072, Australia. Fax: +61 3 9662 7853 Internet: Murray.Jensen@csiro.au Hymod project: http://www.msa.cmst.csiro.au/projects/Hymod/ ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/