UPD78F0537DGA(T)-9EV-A NEC, UPD78F0537DGA(T)-9EV-A Datasheet - Page 561

• Manufacturer Part Number: UPD78F0537DGA(T)-9EV-A
• Description: 8BIT MCU, 128K FLASH, 7KB RAM, SMD
• Manufacturer: NEC

Specifications of UPD78F0537DGA(T)-9EV-A

• Controller Family/series: UPD78
• No. Of I/o's: 55
• Ram Memory Size: 7KB
• Cpu Speed: 20MHz
• No. Of Timers: 8
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 128KB
• Oscillator Type: External, Internal

24.5 Cautions for Low-Voltage Detector
(V
(1) When used as reset
(2) When used as interrupt
(1) When used as reset
(2) When used as interrupt
LVI
In a system where the supply voltage (V
<Action>
The system may be repeatedly reset and released from the reset status.
In this case, the time from release of reset to the start of the operation of the microcontroller can be arbitrarily set
by taking action (1) below.
Interrupt requests may be frequently generated. Take (b) of action (2) below.
After releasing the reset signal, wait for the supply voltage fluctuation period of each system by means of a
software counter that uses a timer, and then initialize the ports (see Figure 24-9).
(a) Confirm that “supply voltage (V
(b) In a system where the supply voltage fluctuation period is long in the vicinity of the LVI detection voltage, wait
Remark If bit 2 (LVISEL) of the low voltage detection register (LVIM) is set to “1”, the meanings of the above
), the operation is as follows depending on how the low-voltage detector is used.
“supply voltage (V
of the LVI interrupt by using bit 0 (LVIF) of the low-voltage detection register (LVIM). Clear bit 0 (LVIIF) of
interrupt request flag register 0L (IF0L) to 0.
for the supply voltage fluctuation period, confirm that “supply voltage (V
detecting the falling edge of V
edge of V
words change as follows.
• Supply voltage (V
• Detection voltage (V
DD
, using the LVIF flag, and clear the LVIIF flag to 0.
DD
) < detection voltage (V
DD
)
LVI
CHAPTER 24 LOW-VOLTAGE DETECTOR
DD
) → Detection voltage (V
, or “supply voltage (V
→ Input voltage from external input pin (EXLVI)
DD
DD
) ≥ detection voltage (V
) fluctuates for a certain period in the vicinity of the LVI detection voltage
User’s Manual U17260EJ6V0UD
LVI
)” when detecting the rising edge of V
DD
EXLVI
) < detection voltage (V
LVI
= 1.21 V)
)” when detecting the falling edge of V
DD
) ≥ detection voltage (V
LVI
)” when detecting the rising
DD
, in the servicing routine
LVI
)” when
DD
561
, or