External Memory Interface
3-14 ADSP-21368 SHARC Processor Hardware Reference
In Table 3-6, P = 0xE00000. Therefore, the total number of external
memory instructions for a 16-bit wide SDRAM memory is 14 million.
Table 3-5. Logical Versus Physical Address Mapping, 32-Bit SDRAM
Memory
Logical Address Dispatched
by Program Sequencer
Physical Address Observed
on the External Address Bus
Data
31 0
0x200000 0x300000 Instr0[31:0]
0x300001 Instr1[15:0] Instr0[47:32]
0x200001 0x300001 Instr1[47:16]
0x300002 Instr2[31:0]
0x200002 0x300002 Instr3[15:0] Instr2[47:32]
0x300003 Instr3[47:16]
... ...
...
... ...
...
0xFFFFFF 0x17FFFFE InstrP[31:0]
0x17FFFFF 0000 InstrN[47:32]
Table 3-6. Logical Versus Physical Address Mapping, 16-Bit SDRAM
Memory
Logical Address Dispatched
by Program Sequencer
Physical Address Observed
on the External Address Bus
Data
16 0
0x200000 0x600000 Instr0[15:0]
0x600001 Instr0[31:16]
0x600002 Instr0[47:32]