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Old 08-14-2013, 03:17 AM   #1
biyabani
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Registered: Mar 2013
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Uart problem in kernel


Hi,
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,
MOHAMMAD BIYABANI.
 
Old 08-14-2013, 01:46 PM   #2
jpollard
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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
biyabani
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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,
Md.Biyabani.
 
  


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