From mboxrd@z Thu Jan  1 00:00:00 1970
From: chris@techworks.ie (Christian Gagneraud)
Date: Tue, 24 May 2011 14:46:36 +0100
Subject: External serial 8250/16550
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	<4DDB3489.2020809@nlink.com.br>
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To: linux-arm-kernel@lists.infradead.org
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On 24/05/11 05:31, Paulo Fragoso wrote:
> On 19-05-2011 17:13, Paulo Fragoso wrote:
>>
>> This explain constant output on COMA from TL16C2550 and COMB is
>> detected at boot time but doesn't work.
>>
>> I will research what can be happening but what can be wrong with NCS1
>> and NCS2?
>
> All is working at boot time and NCS1 was correctly programed in bootstrap.
>
> But no data out at serial line I'm testing enabling getty in inittab.
>
> NCS1, NCS2, IOW and IOR are working how expected by the SMC config:
>
> static struct sam9_smc_config tms_uart_smc_config = {
> .ncs_read_setup = 0,
> .nrd_setup = 2,
> .ncs_write_setup = 0,
> .nwe_setup = 2,
>
> .ncs_read_pulse = 5,
> .nrd_pulse = 4,
> .ncs_write_pulse = 4,
> .nwe_pulse = 3,
>
> .read_cycle = 10,
> .write_cycle = 9,
>
> .mode = AT91_SMC_READMODE | AT91_SMC_WRITEMODE |
> AT91_SMC_EXNWMODE_DISABLE | AT91_SMC_DBW_8 | AT91_SMC_BAT_WRITE,
> .tdf_cycles = 3,
> };
>
> Why isn't there any data on TX for COMA or COMB?

Hi Paulo,

I will have soon to do the same job on a SAM9G20 (but with a Quad UART). 
Did you try to access the registers of the UART? (You can do that from 
userspace: 
ftp://ftp.embeddedarm.com/ts-arm-sbc/ts-7260-linux/sources/peekpoke.tar.gz). 
I think The UART has a scratch register, you could test if you can write 
and read back the data. Do you have any error messages in your logs?
Have you try to use the stty program on your serial port, eg: stty -F 
/dev/ttySXYZ raw -clocal.
Perhaps your problem is on the transceiver side, have you try to tie Tx 
and Rx together and then read write date to the serial port from your 
embedded system?

Chris


>
> Paulo.
>
>
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