K
ADSC
ADSP
A0 – A14
BLOCK DIAGRAM (See Note)
ADV
BURST LOGIC
Q0
A0
Q1
CLR
A1
INTERNAL
A0′ ADDRESS
15
A1′
32K x 9
MEMORY
ARRAY
ADDRESS
REGISTER
A1 – A0
15
2
A2 – A14
9
9
WRITE
W
REGISTER
DATA–IN
REGISTERS
S0
ENABLE
S1
REGISTER
OUTPUT
BUFFER
G
9
DQ0 – DQ8
NOTE: All registers are positive–edge triggered. The ADSC or ADSP signals control the duration of the burst and the start of the
next burst. When ADSP is sampled low, any ongoing burst is interrupted and a read (independent of W and ADSC) is per-
formed using the new external address. When ADSC is sampled low (and ADSP is sampled high), any ongoing burst is
interrupted and a read or write (dependent on W) is performed using the new external address. Chip selects (S0, S1) are
sampled only when a new base address is loaded. After the first cycle of the burst, ADV controls subsequent burst cycles.
When ADV is sampled low, the internal address is advanced prior to the operation. When ADV is sampled high, the internal
address is not advanced, thus inserting a wait state into the burst sequence accesses. Upon completion of a burst, the
address will wrap around to its initial state. See BURST SEQUENCE TABLE.
BURST SEQUENCE TABLE (See Note)
External Address
A14 – A2
A1
A0
1st Burst Address
A14 – A2
A1
A0
2nd Burst Address
A14 – A2
A1
A0
3rd Burst Address
A14 – A2
A1
A0
NOTE: The burst wraps around to its initial state upon completion.
MCM62486B
2
MOTOROLA FAST SRAM