User guide

19
SmartBook for Renesas R8C/Tiny Microcontrollers
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internal reset condition is exited and the program is executed beginning with the
address indicated by the reset vector FFFCH. The following figure indicates the
reset sequence:
Proper operating conditions are to be initialized to get this hardware reset ready.
Voltage Detection Interrupt Register, D4INT, should be properly initialized for this
purpose. Apart from enabling Voltage Detection circuit (VC27 of VCR2 to 1),
Voltage Detection Interrupt should be enabled (D40 bit of D4INT is set to 1).
Now, whenever the supply passes through Vdet, an interrupt request is generated.
By setting D46 bit of D4INT to 1, the voltage detector circuit generates the hardware
reset instead of interrupt request. This function is meant to keep the controller in
reset condition till the supply voltage rises to the safe operating
level. Because of this, the microcontroller starts up properly
to execute the programs.
2.11 Power on Reset Function:
The Power on Reset function operates on the
top of Hardware Reset 2. This function is
meant to keep the controller in the reset
condition till the supply voltage reaches
to the safe operating level. Without
requiring any external circuit, this
facility safeguards the controller during
power on conditions by having a
resister of about 5K between the reset
and the Vcc pins.
D
a
t
a
4
D
e
s
i
g
n


 Whenever
the supply passes
through Vdet, an interrupt
request is generated. By setting
D46 bit of D4INT to 1, the voltage
detector circuit generates the hardware
reset instead of interrupt request.


 Without requiring any external circuit,
this facility safeguards
the controller during
power on conditions by
having a resister of about
5K between the reset and
the Vcc pins.