MB90F523B(2008) 查看數據表（PDF） - Fujitsu

零件编号

产品描述 (功能)

生产厂家

MB90F523B
(Rev.:2008)

16-bit Microcontroller

Fujitsu 

MB90520B Series

Connection of a bypass capacitor of approximately 0.1 µF between VCC and VSS is recommended to prevent

power supply noise. Connect the capacitor close to the VCC and VSS pins.

• Crystal oscillator circuit

Noise on the X0 and X1 pins can be a cause of device misoperation. Place the X0 and X1 pins, crystal oscillator

(or ceramic oscillator) , and bypass capacitor to ground as close together as possible. Also, design the circuit

board so that the X0 and X1 pin wiring does not cross other wiring.

Surrounding the X0/X1 and X0A/X1A pins with ground in the printed circuit board design is recommended to

ensure stable operation.

• Notes on using an external clock

When using an external clock, drive the X0 pin only and leave the X1 pin open.

The figure below shows an example of how to use an external clock.

Example of how to use an external clock

Open circuit

X0

X1

MB90520B series

• Precautions when not using sub-clock mode

Connect an oscillator to X0A and X1A, even if not using sub-clock mode.

• Treatment of unused pins

Leaving unused input pins unconnected can cause misoperation or permanent damage to the device due to

latchup. Always pull-up or pull-down unused pins using a 2 kΩ or larger resistor.

If some I/O pins are unused, either set as outputs and leave open circuit or set as inputs and treat in the same

way as input pins.

• Treatment of N.C. pins

Always leave N.C. (non connect) pins open circuit.

• Treatment of pins when A/D converter not used

When not using the A/D converter and D/A converter, always connect AVCC = DVCC = AVRH = VCC and AVSS =

AVRL = VSS.

• Sequence for connecting and disconnecting the A/D converter power supply and analog input pins

Do not apply voltage to the A/D and D/A converter power supply (AVCC, AVRH, AVRL, DVCC, DVSS) or analog

inputs (AN0 to AN7) until the digital power supply (VCC) is turned on.

When turning the device off, turn off the digital power supply after disconnecting the A/D converter power

supply and analog inputs. When turning the power on or off, ensure that AVRH and DVCC do not exceed AVCC

(turning the analog and digital power supplies on and off simultaneously is OK) .

• Shared use of general-purpose I/O ports and LCD controller/driver SEG/COM pins

The SEG08 to SEG31 and COM0 to COM3 pins are shared with general-purpose I/O ports. The electrical

ratings for SEG08 to SEG23 and COM0 to COM3 are the same as for CMOS outputs and the electrical ratings

for SEG24 to SEG31 are the same as for N-ch open-drain ports.

DS07-13707-5E

19

Share Link: