User guide

20
SmartBook for Renesas R8C/Tiny Microcontrollers
www.MightyMicons.com
Like the Hardware Reset 2, the internal counter counts
low speed on chip oscillator upto 32 when the supply
crosses Vdet and subsequently releases the internal reset.
The reset conditions of CPU, pins, registers are same as
that of Hardware Reset 1. This power on reset function also
automatically initializes D40 and D46 bits of D4INT registers
to 1 level and gets the Hardware Reset 2 into active condition.
2.12 Software Reset:
The microcontrollers can be reset by software by setting PM03 bit of the PMD
register to 1 level. The reset conditions are same as that of other reset options.
2.13 Reset by Watch Dog Timer:
When the PM12 bit of PM1 register is set to 1, the controller is reset when the watchdog
timer under flows. Then the program is executed from the address indicated by the
reset vector. The CPU gets divide by 8 low speed on chip oscillator as its clock.
2.14 Voltage Detection Circuit:
The Voltage Detection Circuit plays a vital role in device reset operating conditions.
This circuit monitors the supply voltage at Vcc pin with Vdet reference and
generates interrupts or hardware reset depending on the initialization conditions.
This detection circuit becomes active when bit VC27 of Voltage Detection Register
2, VCR2 is set to 1. The following figure gives overview of this circuit.
D
a
t
a
4
D
e
s
i
g
n
VC13 bit indicates
the status of supply
voltage at Vcc
pin. It becomes
zero when
the supply voltage is less than
Vdet and gets one level when
the voltage rises to Vdet
or more.