Datasheet

278
11011B–ATARM–21-Feb-12
SAM3N
Figure 18-3. Code Read Optimization for FWS = 3
Note: When FWS is included between 1 and 3, in case of sequential reads, the first access takes (FWS+1) cycles, the other ones only
1 cycle.
18.3.2.3 Data Read Optimization
The organization of the Flash in 128 bits (or 64 bits) is associated with two 128-bit (or 64-bit)
prefetch buffers and one 128-bit (or 64-bit) data read buffer, thus providing maximum system
performance. This buffer is added in order to store the requested data plus all the data contained
in the 128-bit (64-bit) aligned data. This speeds up sequential data reads if, for example, FWS is
equal to 1 (see Figure 18-4).
Note: No consecutive data read accesses are mandatory to benefit from this optimization.
Figure 18-4. Data Read Optimization for FWS = 1
Flash Access
Buffer 0 (128bits)
Master Clock
ARM Request
(32-bit)
Data To ARM
Buffer 1 (128bits)
0-3
XXX
XXX
Bytes 16-31
@Byte 0 @4 @8
Bytes 0-15 Bytes 16-31 Bytes 32-47 Bytes 48-63
XXX
Bytes 0-15
4-7 8-11 12-15
@12 @16 @20
24-27 28-31 32-35 36-3916-19 20-23 40-43 44-47
@24 @28 @32 @36 @40 @44 @48 @52
Bytes 32-47
48-51
Flash Access
Buffer (128bits)
Master Clock
ARM Request
(32-bit)
XXX
Data To ARM
Bytes 0-15 Bytes 16-31
Bytes 0-15
Bytes 0-3
4-7 8-11 12-15 16-19 20-23
XXX
Bytes 16-31
@Byte 0 @ 4 @ 8 @ 12 @ 16 @ 20 @ 24 @ 28 @ 32
@ 36
XXX
Bytes 32-47
24-27 28-31 32-35