Main Pcb - Brother LX-300 Service Manual

5.3 Main PCB

Fig. 5.3-1 shows a block diagram of the electrical parts.
The Main PCB comprises the CPU, detector circuits (including switch status detection),
motor drive circuits, and power circuits.
S
Main CPU
The main CPU is an 8-bit CMOS microcontroller that controls the overall system.
The main CPU incorporates 1 kB RAM, 32 kB ROM, and 72 I/O ports.
The I/O map for the I/O ports is shown in Table 5.3-1 overleaf.
Fig. 5.3-1 Block Diagram of the Electrical Parts
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