UPD78F0411GA-GAM-AX Datasheet, PDF (497/564 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 22 LOW-VOLTAGE DETECTOR
22.4.2 When used as interrupt
(1) When detecting level of supply voltage (VDD)
• When starting operation
<1> Mask the LVI interrupt (LVIMK = 1).
<2> Clear bit 2 (LVISEL) of the low-voltage detection register (LVIM) to 0 (detects level of supply voltage
(VDD)) (default value).
<3> Set the detection voltage using bits 3 to 0 (LVIS3 to LVIS0) of the low-voltage detection level selection
register (LVIS).
<4> Set bit 7 (LVION) of LVIM to 1 (enables LVI operation).
<5> Use software to wait for an operation stabilization time (10 μs (MAX.)).
<6> Confirm that “supply voltage (VDD) ≥ detection voltage (VLVI)” when detecting the falling edge of VDD, or
“supply voltage (VDD) < detection voltage (VLVI)” when detecting the rising edge of VDD, at bit 0 (LVIF) of
LVIM.
<7> Clear the interrupt request flag of LVI (LVIIF) to 0.
<8> Release the interrupt mask flag of LVI (LVIMK).
<9> Clear bit 1 (LVIMD) of LVIM to 0 (generates interrupt signal when the level is detected) (default value).
<10> Execute the EI instruction (when vector interrupts are used).
Figure 22-7 shows the timing of the interrupt signal generated by the low-voltage detector. The numbers in
this timing chart correspond to <1> to <9> above.
• When stopping operation
Either of the following procedures must be executed.
• When using 8-bit memory manipulation instruction:
Write 00H to LVIM.
• When using 1-bit memory manipulation instruction:
Clear LVION to 0.
User’s Manual U18698EJ1V0UD
495