256
脳
36
脳
2 Bidirectional FIFO
LH543601
TIMING DIAGRAMS (cont鈥檇)
CK
B
t
RWS
R/W
B
t
ES
EN
B
t
RQS
REQ
B
t
A
D
0B
- D
8B
BITS
0-8
BITS
9-17
BITS
18-26
BITS
27-35
BITS
0-8
WORD # n
D
9B
- D
17B
BITS
9-17
BITS
18-26
BITS
27-35
WORD # n+1
BITS
0-8
BITS
9-17
WORD # n
D
18B
- D
26B
BITS
18-26
BITS
27-35
BITS
0-8
WORD # n+1
BITS
9-17
BITS
18-26
WORD # n
D
27B
- D
35B
BITS
27-35
BITS
0-8
BITS
9-17
WORD # n+1
BITS
18-26
BITS
27-35
WORD # n
NOTES:
1. A
0B
is held HIGH for FIFO access.
2. OE
B
is held LOW.
3. WS
0
and WS
1
both are held LOW for single-byte access.
4. Data-access time t
A
, after the rising edge of CK
B
, shown for the
first read cycle, applies similarly for all subsequent read cycles.
WORD # n+1
543601-11
Figure 28. Port B Single-Byte FIFO #1 Read Access for
36-to-9 Funneling
37