CAT28F001 CATALYST [Catalyst Semiconductor], CAT28F001 Datasheet - Page 8

• Manufacturer Part Number: CAT28F001
• Description: 1 Megabit CMOS Boot Block Flash Memory
• Manufacturer: CATALYST [Catalyst Semiconductor]

CAT28F001
READ OPERATIONS
Read Mode
The CAT28F001 memory can be read from any of its
Blocks (Boot Block, Main Block or Parameter Block),
Status Register and Signature Information by sending
the Read Command Mode to the Command Register.
CAT28F001 automatically resets to Read Array mode
upon initial device power up or after exit from deep
power down. A Read operation is performed with both
CE and OE low and with RP and OE high. Vpp can be
either high or low. The data retrieved from the I/O pins
reflects the contents of the memory location correspond-
ing to the state of the 17 address pins. The respective
timing waveforms for the read operation are shown in
Figure 3. Refer to the AC Read characteristics for
specific timing parameters.
Signature Mode
The signature mode allows the user to identify the IC
manufacturer and the type of the device while the device
resides in the target system. This mode can be activated
in either of two ways; through the conventional method
of applying a high voltage (12V) to address pin A9 or by
sending an instruction to the command register (see
Write Operations).
The conventional method is entered as a regular read
mode by driving the CE and OE low (with WE high), and
Figure 3. A.C. Timing for Read Operation
Doc. No. 25071-00 2/98 F-1
ADDRESSES
DATA (I/O)
WE (W)
OE (G)
CE (E)
RP (P)
POWER UP
HIGH-Z
STANDBY
ADDRESS SELECTION
t PHQV (t PWH )
DEVICE AND
t GLQX (t OLZ )
t ELQX (t LZ )
t AVQV (t ACC )
8
ADDRESS STABLE
applying the required high voltage on address pin A9
while the other address line are held at VIL.
A Read cycle from address 0000H retrieves the binary
code for the IC manufacturer on outputs I/O
Catalyst Code = 0011 0001 (31H)
A Read cycle from address 0001H retrieves the binary
code for the device on outputs I/O
CAT28F001T = 1001 0100 (94H)
CAT28F001B = 1001 0101 (95H)
Standby Mode
With CE at a logic-high level, the CAT28F001 is placed
in a standby mode where most of the device circuitry is
disabled, thereby substantially reducing power con-
sumption. The outputs are placed in a high-impendance
state independent of the OE status.
Deep Power-Down
When RP is at logic-low level, the CAT28F001 is placed
in a Deep Power-Down mode where all the device
circuitry are disabled, thereby reducing the power con-
sumption to 0.25 W.
t AVAV (t RC )
t GLQV (t OE )
ENABLED
OUPUTS
t ELQV (t CE )
DATA VALID
OUTPUT VALID
STANDBY
t GHQZ (t DF )
t EHQZ
7
t OH
to I/O
POWER DOWN
0
:
HIGH-Z
7
to I/O
28F001 F05
0
: