G4A-PCB
This PCB board is optionally available. Using this board allows the system to be ready for the G4 protocol. This board is connected to the MCNT board through the Oki�s original MUPIS interface. The block diagram of this board is shown on the next page. This board is connected to the MCNT board with an 80-pin connector (CN1). Sixteen pins of this connector are signals lines dedicated to the G4A board, and the remaining 64 pins are signal lines shared with the optional LAN network board. The LAN network board is connected to the 64-pin connector (CN2) when it is used along with this board. It is connected to the line via the RJ-45 connector (CN3). Data is transferred to/from the CPU on the MCNT board via the 2-KB dual port RAM. When data is sent, the MCNT board causes an interrupt to the G4A board using a CUREQN signal and writes data into the 2-KB dual port RAM. The G4A board expands the data from the dual port RAM in the DRAM, and sends the expanded data to the line via the driver. When data is received, the G4A board causes an interrupt to the MCNT board using an OPREQ signal and writes data from the DRAM into the dual port RAM. The NCNT board reads data from the dual port RAM, expands the data in the DRAM on the MCNT board, and sends the data to the LED head via the IOGA5.
