MB90F523B(2008) 查看數據表（PDF） - Fujitsu

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MB90F523B
(Rev.:2008)

16-bit Microcontroller

Fujitsu 

MB90520B Series

• Conditions when output from ports 0 and 1 is undefined

After turning on the power supply, the outputs from ports 0 and 1 are undefined during the oscillation stabili-

zation delay time controlled by the regulator circuit (during the power-on reset) . The figure below shows the

timing.

Note that this undefined output period does not occur on products without an internal regulator circuit as these

products do not have an oscillation stabilization delay time.

Timing chart for undefined output from ports 0 and 1

VCC (Power supply pin)

Oscillation stabilization delay time*2

Regulator circuit stabilization

delay time*1

PONR (Power-on reset) signal

RST (External asynchronous reset) signal

RST (Internal reset) signal

Oscillation clock signal

KA (Internal operating clock A) signal

KB (Internal operating clock B) signal

PORT (port output) signal

Undefined output time

*1 : Regulator circuit oscillation stabilization delay time : 217/Oscillation clock frequency

(approx. 8.19 ms for a 16 MHz oscillation clock frequency)

*2 : Oscillation stabilization delay time : 218/Oscillation clock frequency

(approx. 16.38 ms for a 16 MHz oscillation clock frequency)

Note : See the “■ PRODUCT LINEUP” section for details of which MB90520B series products have an internal

regulator circuit.

• Initialization

The device contains internal registers that are only initialized by a power-on reset. To initialize these registers,

restart the power supply.

• Notes on using the DIV A, Ri and DIVW A, RWi instructions

Set the corresponding bank registers (DTB, ADB, USB, SSB) to “00H” when using the signed division instruc-

tions “DIV A, Ri” and “DIVW A, RWi”.

If the corresponding bank registers (DTB, ADB, USB, SSB) are set to other than “00H”, the remainder value

produced by the instruction is not stored in the instruction operand register.

• Notes on using REALOS

The extended intelligent I/O service (EI2OS) cannot be used when using REALOS.

Caution on Operations during 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.

20

DS07-13707-5E

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