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Block Diagram and Buses

This section is an overview of the major ICs and buses on the computer’s main logic board.

In this section:

Block Diagram
Main ICs and Buses

Block Diagram

“Figure 2-1” is a simplified block diagram of the main logic board. The diagram shows the input and output connectors, the main ICs, and the buses that connect them together.

Main ICs and Buses

The architecture of the 12-inch PowerBook G4 is designed around the PowerPC G4 microprocessor and the custom Intrepid memory and I/O controller. The Intrepid IC occupies the center of the block diagram.

The microprocessor is connected to the Intrepid IC by a MaxBus with 64 data lines and a bus clock speed of 167 MHz. The Intrepid IC has other buses that connect with the Boot ROM, the main system RAM, the graphics IC, and the Ethernet and FireWire PHY ICs. Each of the components listed here is described in one of the following sections. The buses implemented by the Intrepid IC are summarized in Table 2-1, which is in the section “Intrepid Memory and I/O Device Controller.”

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