[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: use ttyS1 as normal serial port on devboard82?




----- Original Message ----- 
From: "Henrik Jönsson" <henke@xxxxxxx.se>
To: <dev-etrax@xxxxxxx.com>
Sent: Monday, September 29, 2003 2:13 PM
Subject: use ttyS1 as normal serial port on devboard82?


> Is it possible to use ttyS1 (X25 pin header) as a regular serial port? We
> have enabled it in the kernel:
>
> [*]   Serial port 1 enabled
> (No_DTR_RI_DSR_CD) Ser1 DTR, RI, DSR and CD assignment
>
> Correct? Should DTR_RI_DSR_CD be enabled? With these settings the devboard
> crashes when we try "echo HEJ > /dev/ttyS1".
>
> dmesg shows:
> ttyS0 at 0xb0000060 is a builtin UART with DMA
> ttyS1 at 0xb0000068 is a builtin UART with DMA
> ttyS2 at 0xb0000070 is a builtin UART with DMA
>
> We know it's 3.3v levels so we have to use a level-shifter to get standard
> RS232 voltage.
>
> We are already using ttyS0 and ttyS2 so it would be great if tou told us
> it's possible to use ttyS1 as a third serial port!
>
> Regards
> Henke

Shouldn't be any problem, but ser1 (ttyS1) uses same DMA channels as USB,
so you can't use them at the same time.
Latest version of the serial driver supports using interrupt driven transfer
without DMA - I don't think we have published that yet though.

/Johan