[sebhc] what's this emulator?

[Lee Hart]

Andy Becker ab31 at juno.com wrote:
> bought an H89 and an H100 (or is it HZ1000?)... The H89 seems to
> have a mismatch between the serial parameters of the CPU board and
> the terminal board after it boots a disk.

On power-up, there are DIP switches on both the CPU and TLB boards that
set the baud rate of the computer and terminal respectively. They have
to be set for matching baud rates. So, if the CPU and terminal work
together, these DIP switches are both set to match.

When you boot an operating system, it has its own independent baud rate
settings. Most Heath software came configured for 9600 baud, but you
could use the SET options in HDOS or CONFIGUR in CP/M to change it to
whatever you like.

To figure out what is going on, turn on the computer. If you get the
"H:" prompt, then CPU and TLB are set to the same baud rate. Press the
OFF LINE key, then ESC x L, then the OFFLINE key again so it pops back
up. This ESC command sets the TLB to 9600 baud (but leaves the CPU board
baud rate unchanged). If the computer still works (i.e. you can type
things like the B boot command), then the DIP switches are both set for
9600 baud.

If you *lose* communication with the terminal, then the CPU and TLB DIP
switches are probably set to 19200 baud. Press the OFFLINE key, then ESC
x M, then the OFFLINE key again so it pops back up. This ESC command
sets the TLB to 19200 baud. If the computer still works, then the CPU
and TLB were set to 19200 baud.

Now reset the computer, and boot your operating system disk. If the
operating system baud rate it wrong, it will print gibberish where the
sign-on message should be, and it won't respond properly to keystrokes.
To verify, use OFFLINE ESC x L or OFFLINE ESC x M to change the TLB baud
rate. Press OFFLINE so it pops back up, and try "dir <return>". If it
works, then you know all that is wrong is that the software baud rate
doesn't match. Use SET or CONFIGUR to change the operating system baud
rate to match the actual DIP switch baud rate.

> It has some kind of fast replacement motherboard.

The two possibilities are the D-G Super89 or TMSI H-1000. The Super89
basically adds a 4 MHz Z80 and extra RAM. The H-1000 adds this, plus an
8 MHz 8086 which can run MS-DOS.

Hope this helps!
-- 
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart  814 8th Ave N  Sartell MN 56377  leeahart_at_earthlink.net


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