Computer Hardware User's Guide

32-Bit-Wide Memory Interface
10-24
Case 3: 32-Bit-Wide Memory With 32-Bit Data-Type Size
When the data size is 32 bits, the ’C32 does not shift the internal address
before presenting it to the external address pins. In this case, the memory
interface copies the value of the internal address bus to the respective external-
address pins. Also, the memory interface activates STRBx_B3
through
STRBx_B0 pins during accesses. Figure 10–13 shows a functional diagram
of the memory interface for 32-bit-wide memory with 32-bit data size.
Figure 10–13. Functional Diagram for 32-Bit Data Size and 32-Bit External-Memory Width
A23
A22
A21
A20
.
.
.
A2
A1
A0
CS
I/O(7-0)
’C32
A
23
A
22
A
21
A
20
.
.
.
A
2
A
1
A
0
D(31-24)
D(23-16)
D(15-8)
D(7-0)
Memoryinterface
A23
A22
A21
A20
.
.
.
A2
A1
A0
CS
I/O(7-0)
A23
A22
A21
A20
.
.
.
A2
A1
A0
CS
I/O(7-0)
A23
A22
A21
A20
.
.
.
A2
A1
A0
CS
I/O(7-0)
STRBxlogic
STRBx_B3
STRBx_B2
STRBx_B1
STRBx_B0
A
23
A
22
A
21
A
20
.
.
.
A
2
A
1
A
0
’C32’s core address bus