Serial port question

[Warren Block]

On Wed, 30 Jan 2008, Mario Lobo wrote:
> I am doing some experiments with the WL5460AP. I doesn't have a serial
> connector but the RTL8186 does have a UART and the circuit board has a 4 pin
> connector (4-3.3V, 3-TXD, 2-RXD, 1-GND) to the UART. The idea here is to
> rewrite its firmware.

You may have to swap TXD and RXD (null-modem).

> For a better debuging (and possibly de-bricking), I need to access its console
> screen (which it DOES have).
>
> The (lots of) info I gathered says that the connection to the WL5460AP console
> should be at 38400, 8N1, no-flow ctl.
>
> I have set up a proper cable and a line in /etc/ttys like:
> ttyd0	"/usr/libexec/getty 3wire.38400" vt100	on  secure

I would set that back to default.  /dev/cuad0 is the callout port.

> Using kermit I type:
>
> SET CARRIER-WATCH OFF
> set duplex full
> set session-log binary
> set modem type none
> set line /dev/ttyd0
> set speed 38400
> set flow none
> set serial 8n1
> set terminal echo local
> set terminal newline-mode on
> set terminal debug on
> connect
>
> but I get nothing back.

Try again with /dev/cuad0.  Again, you may have to reverse TXD and RXD 
at one end of the cable.

> Before I start digging for hardware errors, I want to check if my connection
> attempt is being done right and understand better what is going on.
>
> 1) how does this work? ttyd0 goes "through" cuad0 or does it simply "grabs it"
> and sets its speed to 38400. Originally, cuad0 is set to 9600.

See sio(4).  ttyd0 is a "callin" port, while cuad0 is a "callout" port.

> 2) if it goes "through" cuad0, how do I set it to 38400, 8N1, no-flow ctl?

You're telling kermit to set the speed and flow control.  For this 
application, you could probably use cu/tip also:

cu -l /dev/cuad0 -s 38400

> 3) is my ttys line correct?

I don't think so.

-Warren Block * Rapid City, South Dakota USA