Functional Description
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3
ROM/Flash Speeds
The SMC provides the interface for two blocks of ROM/Flash. Access
times to ROM/Flash are programmable for each block. Access times are
also affected by block width. Refer to Table 3-5, Table 3-6, Table 3-7, and
Table 3-8 for specific timing numbers.
Note The information in Table 3-5 applies to access timing when
configured for devices with an access time equal to 12 clock
periods.
Table 3-5. PPC60x Bus to ROM/Flash Access Timing
(120ns @ 100 MHz)
ACCESS TYPE
CLOCK PERIODS REQUIRED FOR: Total
Clocks
1st Beat 2nd Beat 3rd Beat 4th Beat
16
Bits 64
Bits 16
Bits 64
Bits 16
Bits 64
Bits 16
Bits 64
Bits 16
Bits 64
Bits
4-Beat Read 70 22 64 16 64 16 64 16 262 70
4-Beat Write N/A N/A
1-Beat Read (1 byte)2222------2222
1-Beat Read (2 to 8
bytes) 7022------7022
1-Beat Write 2121------2121