M27C800 STMICROELECTRONICS [STMicroelectronics], M27C800 Datasheet - Page 10

• Manufacturer Part Number: M27C800
• Description: 8 Mbit 1Mb x8 or 512Kb x16 UV EPROM and OTP EPROM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

M27C800
Figure 8. Programming and Verify Modes AC Waveforms
Figure 9. Programming Flowchart
10/18
YES
NO
A0-A18
Q0-Q15
BYTEV PP
V CC
E
G
FAIL
= 25
++n
V CC = 6.25V, V PP = 12.5V
CHECK ALL WORDS
NO
2nd: V CC = 4.2V
BYTEV PP =V IH
1st: V CC = 6V
E = 50 s Pulse
VERIFY
n = 0
Addr
Last
YES
YES
tVPHAV
tVCHAV
NO
++ Addr
AI01044B
tAVEL
tQVEL
tELEH
DATA IN
PROGRAM
PRESTO III Programming Algorithm
The PRESTO III Programming Algorithm allows
the whole array to be programed with a guaran-
teed margin in a typical time of 26 seconds. Pro-
gramming with PRESTO III consists of applying a
sequence of 50µs program pulses to each word
until a correct verify occurs (see Figure 9). During
programing and verify operation a MARGIN
MODE circuit is automatically activated to guaran-
tee that each cell is programed with enough mar-
gin. No overprogram pulse is applied since the
verify in MARGIN MODE provides the necessary
margin to each programmed cell.
Program Inhibit
Programming of multiple M27C800s in parallel
with different data is also easily accomplished. Ex-
cept for E, all like inputs including G of the parallel
M27C800 may be common. A TTL low level pulse
applied to a M27C800's E input and V
will program that M27C800. A high level E input in-
hibits the other M27C800s from being pro-
grammed.
Program Verify
A verify (read) should be performed on the pro-
grammed bits to determine that they were correct-
ly programmed. The verify is accomplished with E
at V
6.25V.
VALID
IH
tEHQX
and G at V
tQXGL
VERIFY
tGLQV
DATA OUT
IL
, V
PP
at 12.5V and V
tGHQZ
tGHAX
AI01599
PP
at 12.5V,
CC
at