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Address Multiplexing

Signals A[0] – A[12] and BA[0] – BA[1] on each RAM SO-DIMM make up a 15-bit multiplexed address bus that can support several different types of SDRAM devices. Table 4-2 lists the types of devices that can be used in the PowerBook G4 computer by size, configuration, and sizes of row, column, and bank addresses.

Important

The PowerBook G4 computer supports only the types of SDRAM devices specified in Table 4-2. Other types of devices should not be used with this computer.


Table 4-2 Types of DRAM devices

Device size Device configuration Row address bits Column address bits
64 Mbits 2 M x 8 x 4 12 9
64 Mbits 1 M x 16 x 4 12 8
64 Mbits 512 K x 32 x 4 11 8
128 Mbits 4 M x 8 x 4 12 10
128 Mbits 2 M x 16 x 4 12 9
128 Mbits 1 M x 32 x 4 12 8
256 Mbits 8 M x 8 x 4 13 10
256 Mbits 4 M x 16 x 4 13 9


  

© 2002 Apple Computer, Inc. (Last Updated April 17, 2002)