Configuration
10-13
TMS320C32 Enhanced External Memory Interface
Figure 10–7. STRB Configuration
STRB0_Bx
STRB1_Bx
STRB0_Bx
STRB config
STRB1_Bx

10.3.2 Using Physical Memory Width and Data-Type Size Fields

Consider a ’C32 connected to two banks of external memory. In this configura-

tion, one bank is mapped to STRB0 while the other bank is mapped to STRB1.

The STRB0 bank of memory is 32 bits wide and stores 32-bit data types. The

STRB1 bank of memory is 16 bits wide and stores 16-bit data types. You can

transfer these configurations to the ’C32 by setting the physical memory width

and data-type size fields of the respective STRB0 and STRB1 control registers.

You also must clear the STRB config bit field to 0 since the banks are separate

memories. Note that ‘C32 address pins A23A22A21...A1A0 are connected to the

STRB0 memory bank address pins A23A22A21...A1A0. But ’C32 address pins

A22A21...A1A0 A1 are connected to the STRB1 memory-bank address pins

A23A22A21...A1A0.

Executing the following code on this device results in the data-access

sequence shown in Table 10–2.

1)
2)
3)
4)
5)
6)
7)
8)
9)
LDI
LDI
ADDI
ADDI
ADDI
LDI
LSH
LDI
ADDI
4000h, AR1
*AR1++, R2
*AR1++, R2
*AR1++, R2
*AR1++, R2
900h, AR2
12, AR2
*AR2++, R3
*AR2, R3
; AR1 = 4000h
; R2 = *4000h and AR1 = AR1 + 1
; R2 = R2 + *4001h and AR1 = AR1 + 1
; R2 = R2 + *4002h and AR1 = AR1 + 1
; R2 = R2 + *4003h and AR1 = AR1 + 1
; AR2 = 900h
; AR2 = 900000h
; R3 = *900000h and AR2 = AR2 + 1
; R3 = R3 + 900001h