APPENDIX A- THE CONTROL WORD


       The control word determines the way the PROMENADE works
   In dealing with a particular EPROM. The PROMOS 2.0 CW is
  actually a 16 bit quantity. The low byte is particularly
  important. The low eight bits control things as follows:

       BITS 1,0           00- Set Vpp to 25 volts.
                          01- Set Vpp to 21 volts.
                          10- Set Vpp to 12.5 volts.
                          11- Set Vpp to 5 volts.

       BITS 3,2           00- Apply Vpp to pin 22.
                          01- Apply Vpp to pin 1.
                          10- Apply Vpp to pin 23.
                          11- Set pin 1 low when Vpp is on.

       BITS 5,4           00- PGM pulse at pin 27.
                          01- PGM pulse at pin 22.
                          10- PGM pulse at pin 20.
                          11- No PGM pulse required.

       BIT 6               0- No action at pin 20 on read.
                           1- Invert pin 20 level on read.

       BIT 7               0- Set standby level on pin 20 low.
                           1- Set standby level on pin 20 high.

       The upper byte works as follows:

       BITS 5,4,3,2,1,0    Select particular page of page mode
                           EPROM. Up to sixty four 16k pages.

       BIT 6               0- Page mode indicator off.
                           1- Page mode indicator on.

       BIT 7               Not used.


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