HP Integral PC Manuals

[Rik]

Yes V1.0.0 I think the same it's just designed to keep the motors running.
Maybe to get the media running before the heads touch it, to prevent 
start/stop spots ?
Well the ability to make errors is what makes us human ;-)
The hartbeat should it be some kind of watchdog signal or a sync for 
realtime processing ?

Rik

----- Original Message ----- 
From: "Tony Duell" <ard at p850ug1.demon.co.uk>
To: <cctalk at classiccmp.org>
Sent: Monday, May 05, 2008 7:58 PM
Subject: Re: HP Integral PC Manuals


>> Checked today, and the floppymotor keeps on running...
>
> And you have V1.0 ROMs, yes?
>
> I think we can assume there's not a hardware fualt on all 3 machines (my
> 2 and yours), and that the floppy was designed to keep running. I wonder
> why? The MotorOn line is certainly software-controlled, it's not simply
> tied low or anything.
>
>> Pictures are made and on it's way to you.
>
> Thanks, I've seen them. The ROM module is very different to my V5.0 one.
>
> 2 ohter errors I've spotted in 'my' Integral schematics :-(.
>
> 1) Input 0 of the Interrupt priority encoder should be tied to ground,
> not +5V. In fact this would make no differece to the operation of the
> machine (the only ontput to change state isn't used!).
>
> 2) The commonned pins on the floppy drive connector on the logic B PCB
> are not suprisingig also grounded. I must have just missed off the ground
> symol :-)
>
> Anyother thing that might be of interest is that there's a 10Hz
> 'heartbeat' on the IR1 interrupt line, it comes from the real time clock
> chip.
>
> -tony
>
>
>