Hi Scott, On Thursday 20 November 2008, Scott Wood wrote: > On Thu, Nov 20, 2008 at 01:32:23PM +0100, Laurent Pinchart wrote: > > Instead of rounding the divider down, improve the baud-rate generators > > accuracy by rounding to the nearest integer. > > > > Signed-off-by: Laurent Pinchart <[EMAIL PROTECTED]> > > This makes things worse on mpc8272ads -- the result of the division is > 13.56, but I only get error-free serial output when rounding down. I > don't think the remote end has timing problems, as I don't see this with > any other board.
I get exactly the opposite here with an mpc8248 base board. Rounding down makes 115200bds completely unreliable :-/ Could you measure the serial baudrate with and without the patch using an oscilloscope ? > Possibly the crystal is a little off, That's always possible. > or maybe it's just better to be a little too fast than a little too slow for > some reason? > > Maybe we should change CPM_CLK to be MAIN_CLK/4 rather than MAIN_CLK/16 > when the BRG clock is below a certain frequency. Isn't that the job of the boot loader ? Accuracy would be improved, but power consumption will raise as well :-/ Best regards, Laurent Pinchart _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev