MB9B460R Datasheet, PDF (56/166 Pages) Cypress Semiconductor – 32-Bit ARM® Cortex® - MF FM4 Microcontroller

MB9B460R Series
7. Handling Devices
Power supply pins
In products with multiple VCC and VSS pins, respective pins at the same potential are interconnected within the device in order to
prevent malfunctions such as latch-up. However, all of these pins should be connected externally to the power supply or ground
lines in order to reduce electromagnetic emission levels, to prevent abnormal operation of strobe signals caused by the rise in the
ground level, and to conform to the total output current rating.
Moreover, connect the current supply source with each POWER pins and GND pins of this device at low impedance. It is also
advisable that a ceramic capacitor of approximately 0.1 µF be connected as a bypass capacitor between VCC and VSS near this
device.
Power supply pins
A malfunction may occur when the power supply voltage fluctuates rapidly even though the fluctuation is within the guaranteed
operating range of the VCC power supply voltage. As a rule of voltage stabilization, suppress voltage fluctuation so that the
fluctuation in VCC ripple (peak-to-peak value) at the commercial frequency (50 Hz/60 Hz) does not exceed 10% of the standard
VCC value, and the transient fluctuation rate does not exceed 0.1 V/μs at a momentary fluctuation such as switching the power
supply.
Crystal oscillator circuit
Noise near the X0/X1 and X0A/X1A pins may cause the device to malfunction. Design the printed circuit board so that X0/X1,
X0A/X1A pins, the crystal oscillator (or ceramic oscillator), and the bypass capacitor to ground are located as close to the device as
possible.
It is strongly recommended that the PC board artwork be designed such that the X0/X1 and X0A/X1A pins are surrounded by
ground plane as this is expected to produce stable operation.
Evaluate oscillation of your using crystal oscillator by your mount board.
Sub crystal oscillator
This series sub oscillator circuit is low gain to keep the low current consumption.
The crystal oscillator to fill the following conditions is recommended for sub crystal oscillator to stabilize the oscillation.
• Surface mount type
Size
Load capacitance
• Lead type
Load capacitance
: More than 3.2 mm × 1.5 mm
: Approximately 6 pF to 7 pF
: Approximately 6 pF to 7 pF
Using an external clock
When using an external clock as an input of the main clock, set X0/X1 to the external clock input, and input the clock to X0. X1(PE3)
can be used as a general-purpose I/O port.
Similarly, when using an external clock as an input of the sub clock, set X0A/X1A to the external clock input, and input the clock to
X0A. X1A (P47) can be used as a general-purpose I/O port.
 Example of Using an External Clock
Device
Can be used as
general-purpose
I/O ports.
X0(X0A)
X1(PE3), X1A (P47)
Set as External
clock input
Document Number: 002-04868 Rev.*A
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