Welcome to the most active Linux Forum on the web.
Go Back > Forums > Linux Forums > Linux - Newbie
User Name
Linux - Newbie This Linux forum is for members that are new to Linux.
Just starting out and have a question? If it is not in the man pages or the how-to's this is the place!


  Search this Thread
Old 08-14-2013, 03:17 AM   #1
Registered: Mar 2013
Posts: 65

Rep: Reputation: Disabled
Uart problem in kernel

I am working with ARM9 based LPC3250 controller with linux kernel version 2.6.34 and LPC3250 contains 7 UARTS and i need 6 UARTS for my application.

UART1,UART2 and UART7 are High Speed UARTS
UART3,UART4,UART5 and UART6 are Standard UARTS

But in my working board except UART4 all UARTS are connected

The connection is like below

UART1 and UART2 are connected to one ADM3202(RS-232) (both uarts are high speed uarts)

UART3 and UART5 are connected to second ADM3202(RS-232) (both uarts are standard uarts)

UART6 and UART7 are connected to third ADM3202(RS-232) (one uart (UART7) is high speed and another one is standard uart (UART6))

After booting the kernel via TFTP (TRIVIAL FILE TRANSFER PROTOCOL) and observed that all UART drivers have installed in kernel

My problem is UARTS (U1,2,3,5) are working properly but UART7 and UART6 are not working (some times UART7 is working and some times giving garbage values)?

I have doubt that they are not working due to different types of UARTs are connected to single serial driver (U6 and U7) but not confirm. If so how to solve this problem and if not what could be the other reasons?

Please help me any one i am struct at this problem from many days.

Thanks & Regards,
Old 08-14-2013, 01:46 PM   #2
Senior Member
Registered: Dec 2012
Location: Washington DC area
Distribution: Fedora, CentOS, Slackware
Posts: 4,844

Rep: Reputation: 1478Reputation: 1478Reputation: 1478Reputation: 1478Reputation: 1478Reputation: 1478Reputation: 1478Reputation: 1478Reputation: 1478Reputation: 1478
Sounds almost like the baud rate on those last two are not being set.

One way to identify that is that they would fail from a cold boot, but could work after a warm boot. IF that is the case, then what may be happening is that baud rate isn't getting set before the application tries to use them. If that happens, then the action of setting the baud rate could be rejected/ignored.

I base this on familiarity with older UARTS, not on your specific unit though. So I could be wrong.
Old 08-16-2013, 01:20 AM   #3
Registered: Mar 2013
Posts: 65

Original Poster
Rep: Reputation: Disabled
Thanks for your reply

I am thinking that the problem is due to connected different UARTs to same serial driver in hardware. Any idea regarding this?

Thanks & regards,


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
how to add UART nodes to kernel. mashhur Programming 4 03-20-2012 12:21 PM
Where does uart console get its value of uart port membase? unifoxz Linux - Kernel 1 12-20-2011 03:28 PM
[SOLVED] Power PC PSC UART Kernel Object just not working DamOTclese Linux - Software 1 05-03-2010 07:16 AM
how to modified 16c550 uart driver from kernel 2.4 to 2.6 first1113 Programming 3 03-02-2007 02:24 PM
New kernel doesn't recognize my modem's UART Kanaflloric Linux - Hardware 0 09-28-2004 11:54 PM > Forums > Linux Forums > Linux - Newbie

All times are GMT -5. The time now is 08:20 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration