MB91106 View Datasheet(PDF) - Fujitsu

Part Name

Description

Manufacturer

MB91106

32-bit RISC Microcontroller

Fujitsu 

MB91106 Series

5. Power Supply Pins

When there are several VCC and VSS pins, each of them is equipotentially connected to its counterpart inside

of the device, minimizing the risk of malfunctions such as latch up. To further reduce the risk of malfunctions,

to prevent EMI radiation, to prevent strobe signal malfunction resulting from creeping-up of ground level and

to observe the total output current standard, connect all VCC and VSS pins to the power supply or GND.

It is preferred to connect VCC and VSS of MB91106 to power supply with minimal impedance possible.

It is also recommended to connect a ceramic capacitor as a bypass capacitor of about 0.1 µF between VCC

and VSS at a position as close as possible to MB91106.

6. Crystal Oscillator Circuit

Noises around X0 and X1 pins may cause malfunctions of MB91106. In designing the PC board, layout X0,

X1 and crystal oscillator (or ceramic oscillator) and bypass capacitor for grounding as close as possible.

It is strongly recommended to design PC board so that X1 and X0 pins are surrounded by grounding area for

stable operation.

7. Turning-on Sequence of A/D Converter Power Supply and Analog Input

Make sure to turn on the digital power supply (VCC) before turning on the A/D converter (AVCC, AVRH) and

applying voltage to analog input (AN0 to AN3).

Make sure to turn off digital power supply after power supply to A/D converters and analog inputs have been

switched off. (There are no such limitations in turning on power supplies. Analog and digital power supplies

may be turned on simultaneously.) Make sure that AVRH never exceeds AVCC when turning on/off power

supplies.

8. Treatment of N.C. Pins

Make sure to leave N.C. pins open.

9. Fluctuation of Power Supply Voltage

Warranty range for normal operation against fluctuation of power supply voltage VCC is as given in rating.

However, sudden fluctuation of power supply voltage within the warranty range may cause malfunctions. It is

recommended to make every effort to stabilize the power supply voltage to IC. It is also recommended that by

controlling power supply as a reference of stabilizing, VCC ripple fluctuation (P-P value) at the commercial

frequency (50 Hz to 60 Hz) should be less than 10% of the standard VCC value and the transient regulation

should be less than 0.1 V/ms at instantaneous deviation like turning off the power supply.

10. Mode Setting Pins (MD0 to MD2)

Connect mode setting pins (MD0 to MD2) directly to VCC or VSS.

Arrange each mode setting pin and VCC or VSS patterns on the printed circuit board as close as possible and

make the impedance between them minimal to prevent mistaken entrance to the test mode caused by noises.

11. Turning on the Power Supply

When turning on the power supply, never fail to start from setting the RST pin to “L” level. And after the power

supply voltage goes to VCC level, at least after ensuring the time for 5 machine cycle, then set to “H” level.

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