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CHAPTER 23
μ
PD78P018F, 78P018FY
23.3 PROM Programming
The
μ
PD78P018F and 78P018FY are provided with 60 KB PROM as a program memory. This memory is set in
the PROM programming mode, when it is programmed, by using the V
PP
and RESET pins. When these pins are not
used, process them by referring to
1.5
or
2.5 Pin Configuration (2) PROM programming mode
.
Caution
Write a program to the program memory in an address range of 0000H to EFFFH (specify the last
address EFFFH). The program cannot be written with a PROM programmer that cannot specify
a write address.
23.3.1 Operation mode
The PROM programming mode is set when +5 V or +12.5 V is applied to the V
PP
pin or when a low-level signal
is applied to the RESET pin. In this mode, the operation modes shown in Table 23-4 can be set by using the CE,
OE, and PGM pins.
By setting the read mode, the contents of the PROM can be read.
Table 23-4. Operation Modes for PROM Programming
Pin
Operation Mode
Page data latch
L
+12.5 V
+6.5 V
H
L
H
Data input
Page write
H
H
L
High impedance
Byte write
L
H
L
Data input
Program verify
L
L
H
Data output
Program inhibit
×
H
H
High impedance
×
L
L
Read
+5 V
+5 V
L
L
H
Data output
Output disable
L
H
×
High impedance
Standby
H
×
×
High impedance
Remark
×
: L or H
(1) Read mode
The read mode is set by setting CE = L and OE = L.
(2) Output disable mode
The data output goes into a high-impedance state and the output disable mode is set when OE = H.
When two or more
μ
PD78P018F’s or 78P018FY’s are connected to the data bus, therefore, data can be read
from any one of the devices by controlling the OE pin.
RESET
V
PP
V
DD
CE
OE
PGM
D0-D7