1 Aug 2006 02:28
Re: AT91 - Achieving UART baud rate of 921600 bps
Foo Tze Wan <twfoo <at> autostar.com.sg>
2006-08-01 00:28:14 GMT
2006-08-01 00:28:14 GMT
Chip and all, Just to update the group after about 2 weeks... Thanks for all the assistance! History: My group had wanted to test the AT91RM9200 UART transmission and reception at 921600 bps. (Send from one UART and receive on another.) I am using the 2.6.17 kernel + the PDC patch from http://maxim.org.za. Status: I have managed to compile, but was still not able to run well without errors at 921600 bps. My group found that the TTL to RS232 transceiver on the DK board was spec at maximum 230400 bps. This could be causing some errors. We will be trying to get a transceiver with higher max baud to try. Thanks again, Tze Wan On Fri, 14 Jul 2006, Chip Coldwell wrote: > If you need a cross-compiler, you can get the one I built and used > from > > http://frank.harvard.edu/~coldwell/toolchain/ > > The easiest thing to do is download the rpm packages; they were built > on Red Hat Enterprise Linux 4, but should work fine on Fedora Core 5 > or SuSE -- if they don't, let me know. >(Continue reading)
>
> Attached is also a patch for arch/arm/mach-at91rm9200/time.c
> which removes the annoying, but harmless (?) 'BUG: soft lockup
> detected on CPU#0!' message when exiting suspended states.
>
> And a patch for drivers/usb/host/ohci-at91.c which fixes the increase
> in user count of usb clocks when mixing 'standby' and 'mem' suspend
> states resulting in suspend failures. Inside is also a small fix for
> disabling
> the second usb port on non-BGA parts - I've got one.
>
Hi Savin,
thank you for the patch.
I am testing your patch on my custom AT91 board,
I can confirm that the "soft lockup" message message no longer appears.
About low power tests I am facing to problems with
echo mem > /sys/power/state
normal 189 mA
standby 169 mA wake up with chars from debug port
mem 144 mA doesn't wake up
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