MB90F548GPF datasheet(20/70 Pages) CYPRESS

20 / 70 page

Document Number: 002- 07696 Rev. *A

Page 20 of 70

MB90540G/545G Series

(13) Initialization

In the device, there are internal registers which are initialized only by a power-on reset. To initialize these registers, please turn on

the power again.

(14) Directions of “DIV A, Ri” and “DIVW A, RWi” instructions

In the Signed multiplication and division instructions (“DIV A, Ri” and “DIVW A, RWi”) , the value of the corresponding bank register

(DTB, ADB, USB, SSB) is set in “00H”.

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

result of the instruction is not stored in the register of the instruction operand.

(15) Using REALOS

The use of EI2OS is not possible with the REALOS real time operating system.

(16) 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.

Oscillation setting time*2

Power-on reset*1

VCC (Power-supply pin)

PONR (power-on reset) signal

RST (external asynchronous reset) signal

RST (internal reset) signal

Oscillation clock signal

KA (internal operation clock A) signal

KB (internal operation clock B) signal

PORT (port output) signal

High-impedance

*1 : Power-on reset time : “Period of clock frequency”

 217 (Clock frequency of 16 MHz : 8.19 ms)

*2 : Oscillation setting time : “Period of clock frequency”

 218 (Clock frequency of 16 MHz : 16.38 ms)

 RST pin is “L”

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