Re: Switch settings for Apple II Pllel. Ifce. Card

[pbauer@athena.mit.edu (Paul H Bauer)]

	For the apple parallel card the following was provided by Mr. David
Empson awhile ago when I had the same question.


Apple Parallel Card
 
The Apple Parallel Interface Card has a bank of seven DIP switches near the
top center of the card. ON is UP and OFF is DOWN.
 
Their functions are as follows:
 
SW1-SW3: set the strobe length according to the following table:
 
    SW1    SW2    SW3    Strobe length (microseconds)
    off    off    off     1
    on     off    off     3
    off    on     off     5
    on     on     off     7
    off    off    on      9
    on     off    on     11
    off    on     on     13
    on     on     on     15
 
SW4 selects the polarity of the Strobe pulse: ON = negative, OFF= positive.
 
SW5 selects the polarity of the Acknowledge input:  ON = negative, OFF =
positive
 
SW6 selects the firmware compatibility: ON = "Centronics" ROM (doesn't
automatically send line feed characters after carriage return), OFF =
"Parallel Printer" ROM (does send LF after CR).
 
SW7 enables interrupts if ON (and should be left OFF!)
 
The manual suggests the following settings for most parallel printers:
 
 SW1  off
 SW2  off
 SW3  off           (1 microsecond STROBE pulse)
 SW4   on           (negative STROBE pulse)
 SW5   on           (negative ACK pulse)
 SW6  off           ("parallel printer")
 SW7  off           (no interrupts)
 
 This should work with the HP Laser printer.
 
 Note that the Apple II parallel cards use a non-standard pinout on their
DB-25: you cannot use an IBM PC parallel printer cable. If you don't have an
appropriate cable, I can give you the pinout of the connector, and you may be
able to get one made up.
 
 
 IDE   DB-25 pin   Centronics pin          Function       HP IIP+
 
  1     1                          Data in bit  0
  3     2           19             Signal Ground
  5     3                          Data in bit  2
  7     4           19-30          Signal Ground
  9     5           2              Data bit  0           Data 0
 11     6           3              Data bit  1           Data 1
 13     7           Blocked (pin must be removed from the DB-25 plug)
 15     8           4              Data bit  2           Data 2
 17     9                          NC
 19    10                          NC
 21    11           7              Data bit  5           Data 5
 23    12           8              Data bit  6           Data 6
 25    13           9              Data bit  7           Data 7
  2    14                          Data in bit  4
  4    15           1              Strobe output         Strobe
  6    16           10             ACK input             ACK (Out)
  8    17                          Data in bit  1
 10    18           35             Data in bit  7        Aux Out 2  (Out)
 12    19           12             Data in bit  5        Paper Error (Out)
 14    20           19-30          Signal Ground
 16    21           13             Data in bit  6        Select
 18    22           5              Data bit  3           Data 3
 20    23           6              Data bit  4           Data 4
 22    24           16             Signal Ground
 24    25           32             Data i bit   3        Fault (Out)
                    11                                   Busy (Out)
                    17                                   Earth
                    18                                   +5 Volts  (Out)
                    33                                   Aux Out 1 (Out)
                    14, 15, 31, 34, 36                   No Connection
 
 The other pins are not used with a standard parallel printer. Pins 9 and 10
are not connected. Pins 1, 3, 14, 17, 18, 19, 21, and 25 form an input 8-bit
data bus, which can be used if the card is being used for general purpose
bidirectional parallel data transfer. In order the bits are 0, 2, 4, 1, 7, 5,
6, 3.
 
 Unfortunately, I don't have any documentation on the pin numbers of the
Centronics connector here, so I don't know what the input functions listed
above are used for. They could be any of ERROR, SELECTED, BUSY, or PAPER
EMPTY. I don't think the firmware uses them.
 
 The card cannot drive the INIT, AUTO FEED XT or SELECT pins, which may need
to be tied to +5V or ground to get the printer to function properly.
 
David Empson
dempson@actrix.gen.nz


pbauer@mit.edu