Memory Interface Signals
9-5
TMS320C30 and TMS320C31 External-Memory Interface
Table 9–2. Expansion Bus Interface Signals
Signal
Type
†
Description
Value
After Reset
Idle Status
MSTRB
O/Z
Expansion bus memory access strobe
1
1
IOSTRB
O/Z
Expansion bus peripheral-access strobe
1
1
XR/W
O/Z
Specifies memory (active high) or write (active
low) mode
1
1
XRDY
I
Indicates external expansion interface is ready
to be accessed
NA
‡
Ignored
XA (12–0)
O
Expansion address bus. When the expansion
bus address lines are not in high-impedance
state due to HOLD signal, they keep the last
external expansion bus access.
HI
Address of last external
expansion bus access
XD (31–0)
I/O/Z
Expansion data bus. These signals go to high-
impedance between write accesses.
HIZ
HIZ
† I
Input
O Output
Z High impedance
‡ NA means not affected.