Computer Hardware User's Guide

16-Bit-Wide Memory Interface
10-28
Table 10–11. Example of 8-Bit Data-Type Size and 16-Bit-Wide External Memory
Internal
Address Bus
External
Address Pins
STRB0_B3/A
–1
Active Strobe Byte Enable
Accessed
Data Pins
4000h 1000h 0 STRB0_B0 D
7–0
4001h 1000h 0 STRB0_B1 D
15–8
4002h 1000h 1 STRB0_B0 D
7–0
4003h 1000h 1 STRB0_B1 D
15–8
4004h 1001h 0 STRB0_B0 D
7–0
Case 5: 16-Bit-Wide Memory With 16-Bit Data-Type Size
When the data-type size is 16 bits, the ’C32 shifts the internal address one bit
to the right before presenting it to the external address pins. In this shift, the
memory interface copies the value of the internal-address A
23
to the external-
address pins A
23
and A
22
. Also, the memory interface copies the value of the
internal-address A
1
to the external STRBx_B3/A
–1
pin. Moreover, the memory
interface activates the STRBx_B1 and STRBx_B0 during accesses.
Figure 10–16 shows a functional diagram of the memory interface for 16-bit-
wide memory with 16-bit data-type size.