Inc. Computer Hardware User Manual

REV. B
ADuC812
–48–
12 MHz Variable Clock
Parameter Min Max Min Max Unit Figure
EXTERNAL DATA MEMORY READ CYCLE
t
RLRH
RD Pulsewidth 400 6t
CK
– 100 ns 53
t
AVLL
Address Valid after ALE Low 43 t
CK
–40 ns 53
t
LLAX
Address Hold after ALE Low 48 t
CK
–35 ns 53
t
RLDV
RD Low to Valid Data In 252 5t
CK
– 165 ns 53
t
RHDX
Data and Address Hold after RD 00 ns53
t
RHDZ
Data Float after RD 97 2t
CK
–70 ns 53
t
LLDV
ALE Low to Valid Data In 517 8t
CK
– 150 ns 53
t
AVDV
Address to Valid Data In 585 9t
CK
– 165 ns 53
t
LLWL
ALE Low to RD or WR Low 200 300 3t
CK
–50 3t
CK
+50 ns 53
t
AVWL
Address Valid to RD or WR Low 203 4t
CK
– 130 ns 53
t
RLAZ
RD Low to Address Float 0 0 ns 53
t
WHLH
RD or WR High to ALE High 43 123 t
CK
–40 6t
CK
– 100 ns 53
MCLK
ALE (O)
PSEN (O)
RD (O)
PORT 0 (I/O)
PORT 2 (O)
t
WHLH
t
LLDV
t
LLWL
t
RLRH
t
AVWL
t
LLAX
t
AVLL
t
RLAZ
t
RHDX
t
RHDZ
t
AVDV
A0–A7 (OUT) DATA (IN)
A16–A23 A8–A15
t
RLDV
Figure 52. External Data Memory Read Cycle