Options on the PG-640A are selected using four DIP switches on the CPU board, eight DIP switches on the video board and 12 jumpers on the video board. The switches on the CPU board are:
1. RESERVED. This switch must be OFF.
2. ADDRESS SELECT. When this switch is OFF, the base address of the communications FIFO queue is set to C6000H, when the switch is ON the base address is set to C6400H. This allows two PG-640A's to be installed in the same system unit.
3. COLOR GRAPHICS ADAPTOR ENABLE. When this switch is ON, the color graphics adaptor emulator is enabled. If there already is an IBM color Graphics Adaptor, or equivalent, in the system unit, the emulator section of the PG-640A should be disabled (switch is OFF).
4. TEST/. This switch is always left OFF. See Appendix G for information on the diagnostics programme.
The CGA Emulator's base address can be strapped to one of two locations: that normally occupied by the CGA (Memory Address B8000, I/O Address 3D0) and that normally occupied by the Monochrome Display Adapter (Memory Address B0000, I/O Address 3B0). If the CGA Emulator is strapped to B0000, the user is responsible for initialising the CRTC registers. The CGA Emulator's base address is set using the following jumpers:
Memory B8000, I/O 3D0: 1-4, 2-3, 7-8 IN
Memory B0000, I/O 3B0: 1-2, 4-5, 6-7 IN
The DIP switches on the video board are used to select the DMA channel used by the PG-640A. Follow the table below to choose the appropriate channel. Note: No other board in the system unit may use the same DMA channel. Switch 5 is not used. Switch 1 should be OFF.
Channel 1: SW2 off SW3 off SW4 on SW6 off SW7 off SW8 on
Channel 2: SW2 off SW3 on SW4 off SW6 off SW7 on SW8 off
Channel 3: SW2 on SW3 off SW4 off SW6 on SW7 off SW8 off
Note: The PG-640A is shipped with Channel 1 selected.
The video sync is normally only available on Pin 4 of the video connector. A jumper can be set to have a composite sync added to the green video signal found on pin 2 of the video connector. See the following table.
Normal Pins 5-6 OUT
Sync On Green Pins 5-6 IN