1 Aug
2004
1 Aug
'04
12:38 a.m.
Most often I build small 'emulators' that use a microcontroller and an
EPROM.
Using a PC parallel port should work just fine. You need to monitor the
DEVICE
COMMAND flag from the I/O board.
At power up, or following a PRESET operation, DEVICE COMMAND will be
asserted, and the PC or emulator should pre-clock the interface DEVICE FLAG
input to clear this 'false' request.
Once pre-clocked, eash assertion of DEVICE COMMAND should be followed
by sending the 8-bit parallel data, then strobing DEVICE FLAG. A
correct load will
halt with 102077 in the S-register.
If your directly connecting the PC to the HP, be careful about ground
loops and
latchup issues if both devices are not powered up at the same moment.
If you need
to power the emulator up seperately from the HP I'd reccomend some form of
isolation.
Dwight K. Elvey wrote:
From: "Bob
Shannon" <bshannon(a)tiac.net>
Jay West wrote:
What data source are you using? I was thinking of connecting
this board to the parallel port of my PC to make the PC look like
an external drive.
Dwight
<snip>
1816-0420 No clue
Paper tape. This is the 'fastest' easy way to bootstrap an HP 1000.
Use this with a 12566 microcircuit I/O board, and you can load a 31K word
boot image in less than 2 seconds, faster than many stock HP disk drives.
Use this boot rom with the emulator I'm
building for you. I'll supply a
cable and jumper settings for the I/O card (gnd true).