I/O ports Argentine Airglow Spectrometer

Argentine Airglow Spectrometer instrument control reads the following inputs from the instrument interface:

Scan limit switches (2 bits)
Photon counter status information (1bit)
Photon count/overflow (19 bits)
Temperature sensors (2 x 1 bit),

The program outputs the following control signals to the instrument hardware:

Stepping motor forward/reverse and step pulse (2 bits)
Photomultiplier power supply on/off (1 bit)
Shutter control (1 bit)
Counter control (gate time, reset/start; 4 bits)

Control program also reads Real Time Clock, System Software Clock, Printer Port Status signals and disables/enables Interrupt Controller Channels.

Other input/outputs: Filter Code (2 bits) does not change and Filter Change output is not used, in normal operation (disabled).

Details:

PC interface for Argentine Airglow Spectrometer
1. Address assignment:  238-23F  = base address 238 + x, x=0,...,7
2. Port assigment:

Port #  bit        INPUT                      OUTPUT
----------------------------------------------------------------------------
         0         D0                         D0 \  timer
         1         D1                         D1    select
         2         D2                         D2 /  ("CO")
238      3         D3  LSB                    D3 PM HiVolt relay
         4         D4  photon                 D4 counter reset
         5         D5  counter                D5 stepping motor forw/reverse
         6         D6                         D6 relay 2 (filter change)
         7         D7                         D7 relay 3 (shutter)
----------------------------------------------------------------------------
         0         D0         
         1         D1         
         2         D2                         stepping motor
239      3         D3  MSB                    pulse
         4         D4  counter                (1 bit)
         5         D5                               
         6         D6  
         7         D7         
----------------------------------------------------------------------------
         0         D0  detector temp. T1      D0  relay 4 
         1         D1  upper limit sw         D1
         2         D2  lower limit sw         D2 
23A      3         D3  P2    filter..         D3
         4         D4  P1       ..pos         D4
         5         D5  available              D5
         6         D6  count ready            D6
         7         D7  filter temp. T2        D7
----------------------------------------------------------------------------
         0         D0  counter carry bit0
         1         D1  counter carry bit1
         2         D2  counter overflow
23B      3         D3  available
         4         D4  available
         5         D5  available 
         6         D6  available
         7         D7  available
--------------------------------------------------------------------------