NEC PD754144 - Manual (Page 81)

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 µs)
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.)