UPD70F3793GC-UEU-AX Datasheet, PDF (865/1113 Pages) Renesas Technology Corp – RENESAS MCU V850ES/Jx3-L Microcontrollers

V850ES/JG3-L
CHAPTER 23 STANDBY FUNCTION
(2) Exiting the RTC backup mode (when an external reset has occurred)
After entering the RTC backup mode, if an external reset signal (RESET) is generated, execute the settings
described in (1) (a) <i> Initial settings for RTC backup mode. If the VDD voltage goes outside the
guaranteed operating range, it is necessary to generate an external reset signal (RESET). Restore the VDD
voltage to greater than 2.3 V.
(3) Exiting the pre-RTC backup mode (when an external reset has not occurred)
If the VDD voltage has not dropped to the level at which an external reset signal (RESET) is generated after
setting the pre-RTC backup mode, the VDD voltage will rise, and once it reaches the level of the LVI voltage,
an INTLVI interrupt request signal will be generated, causing the system to exit STOP mode. The RETI
instruction that is subsequently executed in step <9> in (1) (b) INTLVI interrupt servicing routine causes
the processing to exit the INTLVI interrupt servicing routine, at which point the INTLVI interrupt that was held
pending when the LVIM.LVIF bit was set to 0 will be acknowledged. At this time, execute the following
processing:
(a) INTLVI interrupt servicing routine
After an INTVI interrupt is generated and the normal STOP mode is exited, execute the following
processing routine.
<1> Read the low-voltage detection flag (LVIM.LVIF) and confirm that LVIM.LVIF = 0.
<2> Clear SOSCAMCTL.AMPHS to 0 (specific sequence), and set the subclock (fXT) to normal
oscillation.
<3> Clear RTCBUMCTL0.RBMSET to 0 (specific sequence), and exit the pre-RTC backup mode.
<4> NOP
<5> If necessary, allow EIs and NMIs.
Figure 23-2 shows the RTC backup mode state transition diagram, and Figures 23-3 and 23-4 show the RTC
backup mode setting flow charts.
R01UH0165EJ0700 Rev.7.00
Sep 22, 2011
Page 865 of 1113