Home Page Forums MAME MAME Olivetti M20 emulation status?

The COM port 8251 needs to have an RS232 port abstraction added to it, at which point you would be able to reroute it to a telnet port.

ETA: I assume it would probably need some interrupt lines hooked up as well.

Could you point me to another target doing this? As an example.

The m20 already does it for the keyboard but you'd want to make it generic like in the isbc driver which also shows the rs232 status lines.

I added it. Use with "mame m20 -rs232 null_modem -bitbngr socket.127.0.0.1:4321" and the default is 9600,8n1. Couldn't really test it though as I don't know how the serial port is addressed in pcos.

Seems to work.

I've put a simple terminal program up at ftp://ftp.groessler.org/pub/chris/olivetti_m20/misc/asm-snippets/bin/dt.cmd and ftp://ftp.groessler.org/pub/chris/olivetti_m20/misc/asm-snippets/binutils/dt.s (source code).

Thank you very much!

Hmm, not quite...

The simple terminal program works, but when I redirect console input and output to the serial line, I'm receiving garbage characters in the telnet session. You can reproduce it like this:

After a fresh boot of PCOS 2.0h, type the following:

0> rs232
0> +scom:
0> +dcom:

Now console input and output also comes from/goes to the serial line.

Now type e.g. "vl" on either telnet or the console window and you'll get garbage output in the telnet session.

It's sending everything with the top most bit set so it works if you set the bitbanger output to 7bits but then the input doesn't work. Maybe if there's a telnet client which supports 7bit ascii, putty doesn't appear to.

Ah, PCOS' rs232 settings were wrong. dt.cmd sets them to 9600,8n1, but when redirecting you have to set them before.

Try

0> sc com:,9600,,1,8,,on,4096

Now it's working fine.

You can see current settings with

0> sc com:

Andreas, who contributed to this thread earlier, turned out to be collecting the MFA Microcomputer as well, so we've exchanged emails again. He asked me about the state of the M20, and this prompted me to fire up the driver again.

crazyc had the APB (alternate processor board) for the m20 running, but I can't remember for my life how to activate it ... the BIOS selection menu has an APB item, but I can't change it to anything different than "default".