Precautions On Handling Power Supplies - Fujitsu FR60 Hardware Manual

2.2

Precautions on Handling Power Supplies

This section provides precautions on power supplies with regard to pin handling and
processing when power is turned on.
■ Processing after Power-on
Immediately after power-on, be sure to apply a reset that initializes settings (INIT) from the INIT
pin.
To provide for an oscillation stabilization wait time and regulator stabilization wait time
immediately after power-on, continue to input the "L" level to the INIT pin as long as the
oscillation stabilization wait time required by the oscillating circuit. (Initialization by INIT from the
INIT pin sets the oscillation stabilization wait time to the minimum value.)
■ External Clock Input after Power-on
After power-on, be sure to input an external clock until the oscillation stabilization wait is
canceled.
■ Indeterminate Output when the Power Is Turned On
When the power is turned on, the output pin may remain unstable until the internal power supply
becomes stable.
■ Notes on Using the Internal DC-DC Regulator and A/D Converter
The MB91301 series contains a regulator. Be sure to supply power to the V
add a bypass capacitor of about 4.7 µF for the regulator to the C pin.
The regulator contains an A/D converter and supplies power to AV
a capacitor of at least 0.05 µF between the AVR and AV
Figure 2.2-1 Notes on Using the Internal DC-DC Regulator and A/D Converter
3.3V
3.3V
Vcc
AVcc
AVRH
AVR
AVss/AVRL
Vss
GND
CHAPTER 2 HANDLING THE DEVICE
/AVRL pins.
SS
C
Vss
MB91301
pin at 3.3 V and
CC
at 3.3 V. Be sure to insert
CC
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