--- In RoboBricks2@yahoogroups.com, Brandon Blodget <bbhome@...> wrote:
>
> >The pins on the WRTSL54GS are 1 through 5 with pin 4
> >being a no-connection. In addition, pin 1 is 3.3V
> >which is not needed. Thus, only three wires are used:
> >
> >Router Pin2 => Max232 Pin 9 (TX)
> >Router Pin3 => Max232 Pin 7 (RX)
> >Router Pin5 => Max232 pin 11 (Ground)
> >
> >In addition, there is a voltage divider. I have a
> >330 Ohm resistor between Max232 Pins 7 and 10.
> >I have a 470 Ohm resistor between Max232 Pins 2 and 7.
> >This provides a voltage divider of .5875=(470/(470+33)).
>
> >The signal from the router comes out of router-pin3
> >at between 0 and 3.3V and lands on max232-pin9 which
> >is forwared to the TTL compliant input of the WireHost.
> >The WireHost response comes in on Max232-pin10 a 0 to 5V
> >is divided down to 0-2.93V and sent on to the router-pin2.
>
> Hi Wayne,
>
> Thanks for the additional information. I still have not got this
> working yet.
>
> One thing that is a little confusing to me is that above you say
>
> >Router Pin2 => Max232 Pin 9 (TX)
>
> and then later
>
> >The signal from the router comes out of router-pin3
> >at between 0 and 3.3V and lands on max232-pin9
>
> I think it should say "The signal from the router comes out of
> router-pin*2* ..."

You are correct, that is a typo on my part.

> Anyway, I found that I had "router pin3 -> max232 pin 9" and "router
> pin2 => max232 Pin 7", so I swapped them but still no joy. I have also
> built the voltage divider as you have specified.
>
> One thing that seems a little odd to me is Ground. I've verified that
>
> >Router Pin5 => Max232 pin 11 (Ground)
>
> But Max232 pin 11 is not connected to Max232 pin 15. It appears it
> should be in the schematic.

For revision C of WireHost, pin 11 and pin 15 are
connected to ground.

Other things to check are whether you have the baud rate
of microcom set to 115200. Also, be sure to turn off all
flow control if they have any. Actually, I got tired of
microcom and wrote my program own called "Serial". It does
not have any of the annoying dumb menus. I just set the
serial port "/dev/tts/0" and the speed "115200" --

prompt> Serial /dev/tts/0 115200
{connected to serial port}
{type [Esc] to terminate}
prompt>

Let me know if you want "Serial".

To test microcom/Serial I use a shorting block on
pins 2 and 3 of the router. If that causes echoing
to show up/go away, that means that microcom/Serial
is working.

Bill and I do Robotics on Tuesdays (i.e. tomorrow)
from about 11:30 (lunch) to 3:00'ish. If you want to swing
by my house, we can probably spend a few minutes switching
between boards and routers until we have something that
works. If you are interested, please call me at 408-245-4130.

Alternatively, this Wednesday evening is the HBRC meeting
and I can bring my router and stuff and we try and scrounge
a few minutes after show and tell.

Please let me know,

-Wayne