Hi, how did you get hold of your yamaha ??
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-----Original Message-----
From: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Newsgroups: local.msx.int
Date: Monday, January 18, 1999 6:31 PM
Subject: NETROM->RS232
>Hello,
>
>I happen to be a owner of a certain YAMAHA - MSX2 computer.
>It's quite an ordinary MSX2 and fully compatible with other MSX2-s, except
>for one
>special feature - it has a special NETROM (32KB) with a serial I/O device
>connected
>to the sideslot (pslot=3 and sslot=3, to be exact). That kind of MSXs with
>NETROMs
>were widely used in the former Soviet Union and they were integrated into
>so called
>"Classroom networks" (Max. 15 computers!).
>
>As I only have that one MSX, I'm wondering now how to connect it to my PC
>by using
>that special serial port. The main problem is that there seems to be no
>(useful) information
>available about that hardware. I have found only some materials describing
>the special
>NETROM's bios functions and basic CALLs which are quite sophisticated and
>assume,
>for example, the teacher computer's permission for any communication. But
>there's nothing
>about the specific hardware and how to program it directly! I can't see any
>other reason
>for that except that this information must have been classified. Probably
>it just wasn't
>desirable if student could "disobey" the teachers veto and communicate with
>other
>computer anyway.
>
>But, as there's probably no msx-networks functioning anymore, I wonder if
>somebody
>could help me on that matter. I would be thankful for any information!
>
>Meanwhile I have conducted my own research and as my latest achievment I
>was able
>to send my first bytes ever from MSX directly to my PC's COM port. I used
>for that a simple
>routine I found when poking around the NETROM and self-made circuit to
>convert the
>msx serial signallevels (approximately -6V & 0) to RS232 (12V & -12V). I
>don't know exactly
>how does the NETROM's routine function though - I just discovered that the
>seems to be
>some intialisation through port #09 (OUT (09),A) and the output goes to the
>port #0e.
>But unfortunately I haven't been able to achieve the opposite - I don't no
>how to receive
>a byte (and also must I use I/O polling or is it interrupt driven etc.)
>
>So, I hope that there's somewhere someone who knows something about that
>issue!
>There must be :-)
>
>Greetings,
>Andres
>
>=======================
>EMail: [EMAIL PROTECTED]
>=======================
>
>
>
>
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