Fujitsu F2MC-16LX Hardware Manual page 38

CHAPTER 1 OVERVIEW
About Crystal oscillator circuit
Noise near the X0/X1 pins and X0A/X1A pins may cause the device to malfunction. Design the printed
circuit board so that X0/X1 pins and X0A/X1A pins, the crystal oscillator (or the ceramic oscillator) and
the bypass capacitor to ground are located as close to the device as possible.
It is strongly recommended to design the PC board artwork with the X0/X1 pins and X0A/X1A pins
surrounded by ground plane because stable operation can be expected with such a layout.
Note on using external clock
If you are using the external clock, you must connect external pins as shown in the Figure 1.7-1.
Figure 1.7-1 illustrates an external clock usage. (under f=7 MHz)
Stabilization of Supply Voltage
A sudden change in the supply voltage may cause the device to malfunction even within the V
voltage operating range. For stabilization reference, the supply voltage should be stabilized so that V
variations (peak-to-peak value) at commercial frequencies (50 MHz to 60 MHz) fall below 10% of the
standard V
as power supply switching.
Crystal oscillator circuit of low voltage use
If you are using the device with voltages of 2.0 V or less, the external crystal oscillator may not oscillate at
power-on. Therefore, It will recommend the use of the external clock.
When the dual-supply is used as a single-supply device.
If you are using only a single-system of the MB90330 series that come in the dual-system product, use it
with X0A=V
Writing to flash memory
For serial writing to flash memory, always make sure that the operating voltage V
3.6 V.
For normal writing to flash memory, always make sure that the operating voltage V
3.6 V.
Ensure that you must write to Flash at the operation voltage V
22
Figure 1.7-1 Method for Using External Clock
supply voltage and the transient regulation does not exceed 0.1 V/ms at temporary changes such
CC
: X1A=OPEN.
SS
X0
OPEN
X1
of 3.0 V to 3.60 V.
CC
supply
CC
ripple
CC
is between 3.13 V and
CC
is between 3.0 V and
CC