MB90487PF データシートの表示（PDF） - Fujitsu

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コンポーネント説明

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MB90487PF

16-bit Proprietary Microcontroller

Fujitsu 

MB90480/485 Series

6. Notes on during operation of PLL clock mode

If the PLL clock mode is selected, the microcontroller attempt to be working with the self-oscillating circuit even

when there is no external oscillator or external clock input is stopped. Performance of this operation, however,

cannot be guaranteed.

7. Proper power-on/off sequence

The A/D converter power (AVCC, AVRH) and analog input (AN0 to AN7) must be turned on after the digital power

supply (VCC) is turned on. The A/D converter power (AVCC, AVRH) and analog input (AN0 to AN7) must be shut

off before the digital power supply (VCC) is shut off. Care should be taken that AVRH does not exceed AVCC. Even

when pins used as analog input pins are doubled as input ports, be sure that the input voltage does not exceed

AVCC.

8. Treatment of power supply pins on models with A/D converters

Even when the A/D converters are not in use, be sure to make the necessary connections AVCC = AVRH = VCC,

and AVSS = VSS.

9. Precautions when turning the power supply on

In order to prevent abnormal operation in the chip’s internal step-down circuits, a voltage rise time during power-

on of 50 µs (0.2 V to 2.7 V) or greater should be assured.

10. Supply Voltage Stabilization

Even within the operating range of VCC supply voltage, rapid voltage fluctuations may cause abnormal operation.

As a standard for power supply voltage stability, it is recommended that the peak-to-peak VCC ripple voltage at

commercial supply frequency (50 Hz to 60 Hz) be 10 % or less of VCC, and that the transient voltage fluctuation

be no more than 0.1 V/ms or less when the power supply is turned on or off.

11. Notes on Using Power Supply

Only the MB90485 series usually uses a 3 V power supply. By setting VCC3 = 3 V power supply and VCC5 = 5 V

power supply, P20 to P27, P30 to P37, P40 to P47 and P70 to P77 can be intefaced as 5 V power supplies

separately from the main 3 V power supply. Note that the analog power supplies (such as AVCC and AVSS) for

the A/D converter can be used only as 3 V power supplies.

Programming into FLASH memory must be performed at an operating voltage (VCC) between 3.13 V and 3.6 V.

12. Treatment of N.C. pins

N.C. (internally connected) pins should always be left open.

13. When the MB90480/485 series microcontroller is used as a single system

When the MB90480/485 series microcontroller is used as a single system, use connections so the X0A = VSS,

and X1A = Open.

14. Writing to FLASH memory

For serial writing to FLASH memory, always ensure that the operating voltage VCC is between 3.13 V and 3.6 V.

For normal writing to FLASH memory, always ensure that the operating voltage VCC is between 3.0 V and 3.6 V.

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