Functional Description
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3-11
3
ROM/Flash Speeds
The Falcon pair 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. The access times for ROM/Flash
are shown in
, and
Table 3-4. PowerPC 60x Bus to ROM/Flash Access Timing when configured
for 180ns Devices
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
68
20
64
16
64
16
64
16
260
68
4-Beat Write
N/A
N/A
1-Beat Read (1 byte)
20
20
-
-
-
-
-
-
20
20
1-Beat Read (2 to 8
bytes)
68
20
-
-
-
-
-
-
68
20
1-Beat Write
19
19
-
-
-
-
-
-
19
19
Table 3-5. PowerPC 60x Bus to ROM/Flash Access Timing when configured
for 120ns Devices
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
52
16
48
12
48
12
48
12
196
52
4-Beat Write
N/A
N/A
1-Beat Read (1 byte)
16
16
-
-
-
-
-
-
16
16
1-Beat Read (2 to 8
bytes)
52
16
-
-
-
-
-
-
52
16
1-Beat Write
19
19
-
-
-
-
-
-
19
19