topic Re: uClinux and serial console in ColdFire/68K Microcontrollers and Processors

uClinux and serial console

s4w2099 — Thu, 30 Dec 2010 14:43:32 GMT

Hello,

I finally got uClinux to boot on my custom hardware with a MCF5249L MPU. I am trying to get the serial console to use another default value. I need 115200 bps. I set the baud rate in the kernel options to this value (device drivers -> character devices -> serial drivers). Then compile and burn to flash but for some reason the baud rate remains at 19200.

Because I am running custom hardware I also set the "core clock frequency" to 119808000 (I am using a 18.432 Mhz oscillator instead of the common 11.28 Mhz one). The core clock divide ratio is set to 2. I have tested my hardware many times before running simple uart test programs from the internal SRAM and everything is working great at any rate I set it to.

I am running kernel uClinux-dist-20101026 the 2.6.x version to be more exact. Anyone experienced with this please let me know if there is anything I am missing to get this to work.

Thanks

Re: uClinux and serial console

hungle — Fri, 31 Dec 2010 18:24:58 GMT

hi s4w2099 !

I'm doing system VoIP, use to MCF53281. I had download uC53281-EVM_R225-2009-AUG-19-release file. But I don't known Where is "void main"? The system is running uClinux 2.6. If you also work about this, please help me guide.

Thanks!

Re: uClinux and serial console

TomE — Sat, 01 Jan 2011 22:03:40 GMT

> I set the baud rate in the kernel options to this value (device drivers -> character devices

> -> serial drivers). Then compile and burn to flash but for some reason the baud rate remains at 19200.

Either the code that uses that configuration isn't running or something else is setting the serial port baud rate.

I don't know anything about that embedded linux specifically, just Linux in general. I assume there's a file system and processes and startup and so-on in there somewhere. I think the "init" process usually starts up the serial ports, and uses information in /etc to initialise them.

Search every file in and under "/etc" on the embedded device for "19200" or "tty" and see what you can find. If the distribution has a "skeleton" for the files that end up in /etc it might be easier to search that instead.

Otherwise arrange for system startup to run "stty" and set the ports up how you want them with that.

Tom