II-5
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
Содержание HL-720
Страница 1: ...SERVICE MANUAL MODEL HL 720 730 730Plus R LASER PRINTER ...
Страница 36: ...II 19 1 3 10 Engine I O HL 720 Fig 2 21 shows the engine interface circuit Fig 2 21 ...
Страница 37: ...II 20 HL 730 730Plus Fig 2 22 shows the engine interface circuit Fig 2 22 ...
Страница 61: ... Fig 3 18 2 4 1 1 1 ...
Страница 92: ...SERVICE MANUAL MODEL HL 760 R LASER PRINTER ...
Страница 109: ...II 8 1 3 4 DRAM Two 4M bit DRAMs x 16bits are used as the RAM Fig 2 6 ...
Страница 113: ...II 12 1 3 10 Engine I O Fig 2 12 shows the engine interface circuit Fig 2 12 ...
Страница 114: ...II 13 1 3 11 Paper Feed Motor Drive Circuit Fig 2 13 ...
Страница 133: ...Appendix 2 Main PCB Circuit Diagram 1 3 CODE UK3227000 B48K272CIR 1 3 NAME ...
Страница 134: ...Appendix 3 Main PCB Circuit Diagram 2 3 CODE UK3227000 B48K272CIR 2 3 NAME ...
Страница 135: ...CODE UK3227000 B48K272CIR 3 3 NAME Appendix 4 Main PCB Circuit Diagram 3 3 ...
