[Simh] Physical serial ports and SIMH

[Gregg Levine]

On Wed, Jun 26, 2013 at 1:17 PM, Brian Knittel <brian at quarterbyte.com> wrote:
> Hi Gregg,
>
> This is an interest of mine too, for some personal and some work
> projects.
>
> The RPi usees 3.3V logic, so you have to use a level-shifting chip to
> use the hardware UARTs with RS-232 or RS-4xx. I've had an RS-232/RPi
> interface sitting on the dining room table half put-together for the
> last 2 months, so I can't tell you yet how well it works.
>
> Re: the USB to RS-232 interface options (most of which, AFAIK, use the
> FTDI chip built into a cable), I have read online accounts of
> instability in the Raspbian drivers -- the interfaces work for a few
> minutes or hours, and then stop working. If true, that makes them
> functionally worthless.
>
> I'd be very interested to hear if anyone has had this experience, or
> has found a USB/RS-232 cable/driver combo that has proven to be stable
> on the RPi.
>
> Brian
>
>
> On 26 Jun 2013 at 11:01, Gregg Levine wrote:
>
> Hello!
> Right now I am tooling up to try out an idea or two concerning the
> PDP-11 emulation. This is to be run on a Raspberry Pi running the
> latest release of their Raspberry specific Debian release. (Also fully
> updated and upgraded.)
>
> The device has the two USB connections ostensibly for a keyboard and
> mouse, but one gentleman I know managed to make use of the serial port
> function on one of them, and attached a USB to serial adapter to one
> of the connections. So obviously I can connect two adapters to the two
> ports there.
>
> But what about the serial port embedded on the GPIO connectors? Can I
> make use of that one?
>
> I know normally that SIMH emulates a chosen computer and only fairly
> recently with some of them do communicate with the outside world via
> Ethernet, but for what I'm planning and working on, it seems to be a
> good fit. Should it work I might be able to upscale the working
> programs to Mr Wilson's product running on an X86 board instead, or
> even an actual PDP-11 model.....
> -----
> Gregg C Levine gregg.drwho8 at gmail.com
> "This signature fought the Time Wars, time and again."
> -=-=-=-=-=-=-=-=-=-=-
> _| _| _|  Brian Knittel
> _| _| _|  Quarterbyte Systems, Inc.
> _| _| _|  Tel: 1-510-559-7930
> _| _| _|  http://www.quarterbyte.com

Hello!
Interesting point. As it happens FTDI makes a module that adds things
to the based Raspberry Pi, here:
http://www.ftdichip.com/Products/Modules/RPi.htm they basically there
explain everything imaginable for the module itself. I suspect based
on what you've stated there's still some unstability in the drivers
that the modules are creating, and, ah, its supposed to be fixed using
the library they describe on an app note, and of course its available
for all forms of Linux.

-----
Gregg C Levine gregg.drwho8 at gmail.com
"This signature fought the Time Wars, time and again."