User`s manual

User’s Manual 55
Figure A-4 shows a typical timing diagram for the Rabbit 3000 microprocessor external
I/O read and write cycles.
Figure A-4. I/O Read and Write Cycles—No Extra Wait States
NOTE: /IOCSx can be programmed to be active low (default) or active high.
T
adr
T
adr
External I/O Read (no extra wait states)
CLK
A[15:0]
External I/O Write (no extra wait states)
CLK
A[15:0]
/IORD
valid
T1
Tw
T1
Tw
T2
valid
T2
/BUFEN
/IOCSx
/IOWR
/BUFEN
D[7:0]
valid
T
setup
T
hold
/CSx
/IOCSx
T
CSx
T
IOCSx
T
IORD
T
BUFEN
T
CSx
T
IOCSx
T
IORD
T
BUFEN
valid
D[7:0]
/CSx
T
CSx
T
IOCSx
T
IOWR
T
CSx
T
IOCSx
T
IOWR
T
BUFEN
T
BUFEN
T
DHZV
T
DVHZ