NEC PD754244 Manuel D’Utilisation
CHAPTER 5 EEPROM
81
User’s Manual U10676EJ3V0UM
5.3 EEPROM Write Control Register (EWC)
The EEPROM write control register (EWC) is an 8-bit register used to control manipulation of EEPROM. Figure
5-1 shows its configuration.
Figure 5-1. Format of EEPROM Write Control Register
ERE
7
EWTC6
6
EWTC5
5
EWTC4
4
EWE
3
EWST
2
–
1
–
0
FCEH
Address
EWC
Symbol
EEPROM read enable flag
ERE
EEPROM
0
EEPROM read disabled (suppresses current)
1
EEPROM read enabled (after 15
µ
s)
Dedicated EEPROM write timer clock selection bit
EWTC6 EWTC5 EWTC4
Selection of count clock
0
0
0
18
× 2
13
/f
X
0
0
1
18
× 2
12
/f
X
0
1
0
18
× 2
11
/f
X
0
1
1
18
× 2
10
/f
X
1
0
0
18
× 2
9
/f
X
1
0
1
18
× 2
8
/f
X
Other than above
Setting prohibited
f
X
= system clock oscillation frequency
EEPROM write enable/disable control bit
EWE
EEPROM write operation
0
Disable
1
Enable
EEPROM write status flag
EWST
Write status
0
EEPROM write enable
1
EEPROM being written (EEPROM writing is not possible. If writing
is attempted, it is ignored.)