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6.3
Programming
The write, verify, and other modes are selected as shown in table 6-3 in PROM mode.
Table 6-3
Mode Selection in PROM Mode (H8/3937, H8/3937R)
CE
Mode
Write
L
Verify
L
Programming
L
disabled
L
H
H
Notation:
L:
Low level
H:
High level
V
:
V
level
PP
PP
V
:
V
level
CC
CC
The specifications for writing and reading are identical to those for the standard HN27C101
EPROM. However, page programming is not supported, and so page programming mode must not
be set. A PROM programmer that only supports page programming mode cannot be used. When
selecting a PROM programmer, ensure that it supports high-speed, high-reliability byte-by-byte
programming. Also, be sure to specify addresses from H'0000 to H'EDFF.
6.3.1
Writing and Verifying
An efficient, high-speed, high-reliability method is available for writing and verifying the PROM
data. This method achieves high speed without voltage stress on the device and without lowering
the reliability of written data. The basic flow of this high-speed, high-reliability programming
method is shown in figure 6-4.
OE
PGM
V
PP
H
L
V
PP
L
H
V
PP
L
L
V
PP
H
H
L
L
H
H
Pins
V
EO
to EO
CC
7
0
V
Data input
CC
V
Data output
CC
V
High i m pedanc e
CC
EA
to EA
16
0
Address input
Address input
Address input
123
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