CAT28F020 CATALYST [Catalyst Semiconductor], CAT28F020 Datasheet - Page 11

• Manufacturer Part Number: CAT28F020
• Description: 2 Megabit CMOS Flash Memory
• Manufacturer: CATALYST [Catalyst Semiconductor]

Erase-Verify Mode
The Erase-verify operation is performed on every byte
after each erase pulse to verify that the bits have been
erased.
Programming Mode
The programming operation is initiated using the pro-
gramming algorithm of Figure 7. During the first write
cycle, the command 40H is written into the command
register. During the second write cycle, the address of
the memory location to be programmed is latched on the
falling edge of WE, while the data is latched on the rising
edge of WE. The program operation terminates with the
next rising edge of WE. An integrated stop timer allows
for automatic timing control over this operation, eliminat-
ing the need for a maximum program timing specifica-
tion. Refer to AC Characteristics (Program/Erase) for
specific timing parameters.
Figure 6. A.C. Timing for Programming Operation
ADDRESSES
DATA (I/O)
WE (W)
OE (G)
CE (E)
V CC POWER-UP
V CC
V PP
& STANDBY
5.0V
0V
V PPH
V PPL
t GHWL
HIGH-Z
SETUP PROGRAM
COMMAND
t VPEL
t DS
t WC
t CH
t WP
t CS
t WPH
DATA IN
= 40H
t AS
LATCH ADDRESS
& DATA
t DH
t DS
t AH
DATA IN
PROGRAMMING
t WP
t CH
11
t DH
t CS
t WHWH1
Program-Verify Mode
A Program-verify cycle is performed to ensure that all
bits have been correctly programmed following each
byte programming operation. The specific address is
already latched from the write cycle just completed, and
stays latched until the verify is completed. The Program-
verify operation is initiated by writing C0H into the
command register. An internal reference generates the
necessary high voltages so that the user does not need
to modify V
Erase) for specific timing parameters.
PROGRAM
COMMAND
t WP
VERIFY
t DS
t WC
DATA IN
= C0H
CC
. Refer to AC Characteristics (Program/
t DH
t CH
t WHGL
t OLZ
t OE
t LZ
t CE
VERIFICATION
PROGRAM
t RC
DATA OUT
VALID
Doc. No. 25037-00 2/98 F-1
V CC POWER-DOWN/
CAT28F020
STANDBY
t EHQZ
t DF
t OH
28F020 F07