M27256-F6 STMICROELECTRONICS [STMicroelectronics], M27256-F6 Datasheet - Page 7

• Manufacturer Part Number: M27256-F6
• Description: NMOS 256K 32K x 8 UV EPROM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Figure 6. Programming and Verify Modes AC Waveforms
Figure 7. Programming Flowchart
YES
NO
FAIL
> 25
++n
V CC
A0-A14
Q0-Q7
V PP
E
G
V CC = 6V, V PP = 12.5V
V CC = 5V, V PP = 5V
CHECK ALL BYTES
E = 3ms Pulse by n
NO
E = 1ms Pulse
VERIFY
n = 1
Addr
Last
YES
YES
tVPHEL
tVCHEL
NO
tAVEL
tQVEL
tELEH
DATA IN
++ Addr
PROGRAM
AI00774B
VALID
tEHQX
DEVICE OPERATION (cont’d)
to a particular M27256 location), before a correct
verify occurs. Up to 25 one-millisecond pulses per
byte are provided for before the over program pulse
is applied. The entire sequence of program pulses
and byte verifications is performed at V
V
When the Fast Programming cycle has been com-
pleted, all bytes should be compared to the original
data with V
Program Inhibit
Programming of multiple M27256s in parallel with
different data is also easily accomplished. Except
for E, all like inputs (including G) of the parallel
M27256 may be common. A TTL low pulse applied
to a M27256’s E input, with V
program that M27256. A high level E input inhibits
the other M27256s from being programmed.
Program Verify
A verify should be performed on the programmed
bits to determine that they were correctly pro-
grammed. The verify is accomplished with E = V
G = V
Optional Verify
The optional verify may be performed instead of the
verify mode. It is performed with G = V
(as opposed t the standard verify which has E =
PP
tQXGL
= 12.5V.
IL
VERIFY
tGLQV
and V
DATA OUT
CC
PP
= 5V and V
= 12.5V.
PP
tGHQZ
tGHAX
= 5V.
AI00759
PP
= 12.5V, will
CC
IL
M27256
= 6V and
, E = V
7/10
IH
IL
,