Interrupt Related To Eeprom Control - NEC PD754144 User Manual

Cautions 1. The write time depends on the system clock oscillation frequency.
2. Set EWTC4-EWTC6 so that the write time is as follows.
With µ PD754144 ··· 18 × 2
With µ PD754244 ··· 4.0 ms MIN., 10.0 ms MAX.
Clear EWE to 0 after writing.
3. Be sure to clear (0) the ERE flag before executing a STOP instruction to disable reading. If
the ERE flag is set (1), a current of approximately 10 µ A always flows in the read circuit.
Therefore, be sure to clear (0) the ERE flag before executing a STOP instruction to stop the
current supply to the read circuit.
4. Be sure to clear (0) the EWE flag before executing a STOP instruction to disable writing.
EWC is set by an 8-bit memory manipulation instruction.
Bits 4 to 6 of EWC are the dedicated EEPROM write timer clock selection bits (EWTC).
EWTC sets the count clock when EEPROM automatic erasure/automatic writing is performed. EEPROM performs
automatic erasure/automatic writing for each time set by EWTC.
Bit 2 of EWC is a write status flag (EWST). This flag can be used to check in 1-bit units whether writing is currently
performed or writing is possible. When writing is started, EWST is automatically write disabled (1). A bit memory
manipulation instruction is used to check this.
RESET input clears all EWC bits to 0.
Example EEPROM is write enabled and the write time is set to 18 × 2
SEL MB15
MOV XA, #01011000B
MOV EWC, XA

5.4 Interrupt Related to EEPROM Control

Table 5-5 shows the interrupt related to EEPROM control.
For the details of the interrupt function, refer to CHAPTER 7 INTERRUPT AND TEST FUNCTIONS.
EEPROM Interrupt EEPROM Interrupt
Interrupt Source
INTEE IRQEE
EEPROM write
end interrupt
Caution The INTOW interrupt (EEPROM overwrite interrupt) used in the µ PD75048 is not provided.
82
CHAPTER 5 EEPROM
8
/f (4.6 ms: f
CC
Table 5-1. Interrupt Related to EEPROM Control
Request Flag Request Flag
IEEE
User's Manual U10676EJ3V0UM
= 1.0 MHz)
CC
8
/f .
X
Vector Table Interrupt Request Flag
Address
VRQ7 When the write time set by
(000EH) EWC has elapsed.
Setting Source