Analog Devices SHARC ADSP-214 Series - DDR2

ADSP-214xx SHARC Processor Hardware Reference 3-87
External Port
The first access does the explicit 32-bit access (which results in the physi-
cal space in 2x16-bit words) while the 2nd 32-bit access does the implicit
transfer. In total there are four read or write commands as shown in
Table 3-16.
DDR2
For a SIMD transfer, the controller can burst the 64-bit data given by the
core and writes it to N and N+1 memory locations. Since the burst length
is 4, SIMD mode transfers can be performed within one burst access.
The first access does the explicit 32-bit access (which results in the physi-
cal space in 2x16-bit words) while the 2nd 32-bit access dperforms the
implicit transfer. In total there is one read or write command per burst of
4x16-bit data as shown in Table 3-17.
Table 3-16. SDRAM SIMD Access
Access Logical x32 Physical x16 Comment
Explicit DM(0x200000) = R0 DM(0x400000) = R0(LSW);
DM(0x400001) = R0(MSW);
No Masking
Implicit DM(0x200001) = S0 DM(0x400002) = S0(LSW);
DM(0x400003) = S0(MSW);
No Masking
Table 3-17. DDR2 SIMD Burst Access
Access Logical x32 Physical x16 Comment
Explicit DM(0x200000) = R0 DM(0x400000) = R0(LSW);
DM(0x400001) = R0(MSW);
DDR2_DM1–0 = low
DDR2_DM1–0 = low
Implicit DM(0x200001) = S0 DM(0x400002) = S0(LSW);
DM(0x400003) = S0(MSW);
DDR2_DM1–0 = low
DDR2_DM1–0 = low
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