Looking for info on HP 9915A

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Wed Jul 2 19:45:01 2003

> pinout of the keyboard connector and any other technical information
> about the box.

The HP85 service manual is on the MoHPC CD-ROMs. There are differences
between the 85 and the 9915A, but they're similar enough that this manual
is a great help. All the major ICs from the 85 turn up in the 9915
(There's one extra custom chip, an I/O translator, that you can find
details of in any of the HP85 interface manuals).

The keyboard connector is a DB25. The pinout is :

1 : Shield
2 : R0
3 : R1
4 : R2
5 : R3
6 : R4
7 : Ground
8 : Ground
9 : R5
10 : R6
11 : R7
12 : R8
13 : R9
14 : C0
15 : C1
16 : C2
17 : C3
18 : C4
19 : C5
20 : C6
21 : C7
22 : Shift/
23 : Ctrl/
24 : Capslock/
25 : Speaker

The keyboard matrix is the same as the 85, and is connected between the
row (Rn) and column (Cn) lines The shift, control, and capslock keys are
connected between the appropriate pin and ground. I am told the speaker
is an 8 ohm unit, connected between pin 25 and ground.

The Control connector, a DA15, has the following pinout :
1 : LED0
2 : LED1
3 : LED2
4 : LED3
5 : LED4
6 : LED5
7 : LED6
8 : LED7
9 : Run/
10 : Test
11 : Power OK
12 : Ground
13 : StartSw/
14 : TestSw/
15 : Shield

It basically carries the signals used on the front panel PCB. LEDn are
the 8 user-definable LEDs. Run and Test are the signals for the 2 LEDs
with those labels on the panel (note that one seems to be inverted, the
other isn't!). The 2 switch signals correspond to the run and test
switches on the panel -- the external switches go between those signals
and ground.

The 4 function keys on the left of the front panel are just the user
definable keys on the HP85, and appear in the keyboard matrix as you'd
expect.

The video connector is composite monochrome video at (US) TV scan rates.
Just about any composite mono monitor will work.

-tony
Received on Wed Jul 02 2003 - 19:45:01 BST