NEC 78K0 Series User Manual page 552

Figure 24-9. Example of Software Processing After Reset Release (1/2)
• If supply voltage fluctuation is 50 ms or less in vicinity of LVI detection voltage
Reset
Initialization
processing <1>
Setting LVI
Setting 8-bit timer H1
(to measure 50 ms)
Clearing WDT
Detection
voltage or higher
(LVIF = 0?)
LVIF = 0
Restarting timer H1
(TMHE1 = 0 → TMHE1 = 1)
No
50 ms has passed?
(TMIFH1 = 1?)
Initialization
processing <2>
Note A flowchart is shown on the next page.
552
CHAPTER 24 LOW-VOLTAGE DETECTOR
; Check the reset source
Initialize the port.
LVI reset
; Setting of detection level by LVIS
The low-voltage detector operates (LVION = 1).
; f = Internal high-speed oscillation clock (8.4 MHz (MAX.)) (default)
PRS
Source: f
Timer starts (TMHE1 = 1).
Yes
No
; The low-voltage detection flag is cleared.
; The timer counter is cleared and the timer is started.
Yes
; Setting of division ratio of system clock,
such as setting of timer or A/D converter
Preliminary User's Manual U17260EJ3V1UD
Note
12
(8.4 MHz (MAX.))/2 ,
PRS
Where comparison value = 102: ≅ 50 ms