SST30VR021-70-C-UN 查看數據表（PDF） - Silicon Storage Technology
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SST30VR021-70-C-UN
Silicon Storage Technology
SST30VR021-70-C-UN Datasheet PDF : 12 Pages
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2 Mbit ROM + 1 Mbit / 2Mbit / 256 Kbit SRAM
ROM/RAM Combo
SST30VR021 / SST30VR022 / SST30VR023
Data Sheet
Address
RAMCS#
TWC
TAW
TCW(2)
TWR(4)
WE#
TAS(3)
TWP(1)
TOH
Data In
High-Z
TDW
Data Valid
TDH
Data Out
TWHZ(5)
TOW
High-Z (6)
(7)
(8)
380 ILL F07.0
Notes:
1. A write occurs during the overlap (TWP) of a low RAMCS# and low WE#. A write begins at the latest transition among
RAMCS# going low and WE# going low: A write end at the earliest transition among RAMCS# going high and WE# going high,
TWP is measured from the beginning of write to the end of write.
2. TCW is measured from the later of RAMCS# going low to the end of write.
3. TAS is measured from the address valid to the beginning of write.
4. TWR is measured from the end of write to the address change.
5. If RAMCS#, WE# are in the read mode during this period, the I/O pins are in the outputs Low-Z state.
Inputs of opposite phase of the output must not be applied because bus contention can occur.
6. If RAMCS# goes low simultaneously with WE# going low or after WE# going low, the outputs remain high impedance state.
7. DOUT is the same phase of the latest written data in this write cycle.
8. DOUT is the read data of new address
9. ROMCS# = VIH
FIGURE 8: SRAM WRITE CYCLE TIMING DIAGRAM
TABLE 8: FUNCTIONAL DESCRIPTION/TRUTH TABLE
Address Inputs
ROMCS#1
RAMCS#1
X
H
H
A17-A0
L
H
A17-A0
L
H
Only AMS3-A0 are valid4
H
L
Only AMS3-A0 are valid4
H
L
Only AMS3-A0 are valid4
H
L
WE#
X2
X2
X2
H
H
L
1. If is forbidden for ROMCS# pin and RAMCS# pin to be “0” at the same time
2. X means Don’t Care.
3. AMS = A16 for SST30VR021, A17 for SST30VR022, and A14 for SST30VR023
4. For SST30VR021: A17 must be fixed to “L” or “H”
For SST30VR023: A15, A16, and A17 must be fixed to “L” or “H”
©2001 Silicon Storage Technology, Inc.
9
OE#
X2
H
L
H
L
H
DQ0-DQ7
Z
Z
Dout
Z
Dout
Din
Standby
Output Floating
ROM Read
Output Floating
RAM Read
RAM Write
T8.4 380
S71135-02-000 4/01 380
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