Main Pcb; Cpu Core - Brother HL-730Plus Service Manual

1.3

Main PCB

1.3.1

CPU Core

<HL-720>
Fig. 2.5 shows the ASIC circuit block on the main PCB.
The CPU core is a Z80 which is driven with a clock frequency of 12.27 MHz. This
frequency is made by dividing the source clock of 24.54 MHz into two in the
oscillator circuit. The address bus is 16 bits and the data bus is 8 bits. The total
memory space is 64 Kbytes. The CPU core access directly only the program ROM
and the working S-RAM, and the DRAM through the DRAM control unit.
NOTE: The ASIC has the functions above.
Fig. 2.5
II-5