FR460 Hardware Set Up
Chapter 1 Minimal System
© Fujitsu Microelectronics Europe GmbH
- 7 -
MCU-AN-300033-E-V13
Power supply
The power supply should be 5 Volts
±
10% for normal usage. If a different supply voltage is
used please refer to the MB91460 data sheet.
1.3 Analog Digital Converter Supply Pins
The analog converter supply pins (AVCC, AVSS, AVRH, AVRL) should be connected even if
the ADC of the MCU is not used. Please refer to our application note
an-900084-ADC
for
using the ADC and pin connection.
1.4 Analog Input Pins
Because the ADC works with an internal sample capacitor the input impedance and external
capacity must be low. Fujitsu recommends an input impedance of not more than 15k Ohm.
Choose the external capacity as low as possible (about 1 nF for EMI protection).
1.5 Reset Pin (INITX)
To reset the MCU a switch connects this pin to VSS (Ground). Additionally a capacitor has to
be connected between VSS and the reset pin for debouncing the switch and for EMI
protection. From experience Fujitsu recommend a capacity of not more than 1 nF (COG). This
capacity covers the most common frequency protection in a wide range. Higher capacities and
high impedance may cause latch-up effects together with an INITX-switch and low EMI
protection.
If the device has no internal pull-up resistor, an external pull-up resistor should be connected.
1.6 VCC18C Pin
A 4.7
I
F...10
I
F (ceramics X7R) capacitor
must
be connected to the C pin of the MCU. This
smooth capacitor is needed to stabilize the internal 1.8V core supply. Otherwise the MCU may
not operate correct or will be damaged in worst case. Please refer to the DS regarding the
specified capacitance value. Also see chapter 2.
1.7 Clock Source
A clock source must be provided to the MCU. Therefore crystals or external clock signals can
be used. For external source pin X0 (X0A) is used whereby pin X1 (X1A) is not connected.
Note: If the sub clock oscillator is not used, connect the X0A pin to ground and leave the X1A
pin open.
Please also refer to the chapter
Introduction/Precautions for Device Handling
in the
corresponding hardware manual for details.
1.8 Mode Pins
The mode pins signalize the MCU the current operation mode. For a single chip system the
mode pins MD2-0 should be connected directly to GND. To avoid entering test mode due to
noise, use a short trace length between each mode pin on printed board and VDD or VSS to
connect pins at low impedance.
