Activating the PCG700
– Turn on the power of the MZ-700
– Set the switch HSW of the PCG700 to the position PCG ( ON )
If the switch HSW is set to the position “NOM” then the PCG700 is deactivated and your MZ-700 uses its standard character set. The MZ-700 character generator works well as if no PCG700 would exist.
If you set the jumper SSW to the position “ON” then the PCG700 can be controlled by software otherwise not. To this the software can activate the PCG700 by setting bit 3 of the PCG700 port $E012 to 0. Setting this bit to 1 will deactivate the PCG700.
POKE $E012,0 : REM PCG700 ON POKE $E012,8 : REM PCG700 OFF
POKE &HE012,0 : REM PCG700 ON POKE &HE012,8 : REM PCG700 OFF
( Details of programming the PCG700 are here )
The PCG can be controlled by software ( bit 3 of port $E012 ) and by hardware ( HSW ). You can prevent the software control by setting the jumper SSW to its position “OFF” even if a software will try to activate it.
The PCG700 uses memory mapped I/O to be controlled by software. This means, the software uses simple I/O commands to control the PCG700. The ports used for all functions are $E010, $E011, and $E012. These ports are exclusively allocated for the PCG700 and cannot be used by other expansions while using the PCG700.
Bank switching must be done to be able to access the ports and/or the V-RAM. Both can be activated by the commands OUT ($E3),A or OUT ($E4),A.
The PCG700 permanently decodes these ports. If you use a special hardware expansion which will not work properly by this decoding then you can set the jumper GSW to its position “OFF”. This will deactivate all data transfer to the PCG700 ( and by this the PCG700 itself ). All PCG700 ports are disconnected from the PCG700 bus if setting GSW to “OFF”.