MB90F342CES datasheet(24/84 Pages) FUJITSU

24 / 84 page

MB90340E Series

13. Stabilization of power supply voltage

A sudden change in the supply voltage may cause the device to malfunction even within the VCC supply voltage

operating range. Therefore, the VCC supply voltage should be stabilized. For reference, the supply voltage should

be controlled so that VCC ripple variations (peak- to-peak values) at commercial frequencies (50 MHz/60 MHz)

fall below 10

% of the standard VCC supply voltage and the coefficient of fluctuation does not exceed 0.1 V/ms at

instantaneous power switching.

14. Port 0 to Port 3 Output During Power-on (External-bus Mode)

As shown below, when the power is turned on in External-Bus mode, there is a possibility that output signal of

Port 0 to Port 3 might be unstable irrespective of the reset input.

15. Notes on Using the CAN Function

To use the CAN function, please set the DIRECT bit of the CAN Direct Mode Register (CDMR) to 1.

16. Flash Security Function (except for MB90F346E)

A security bit is located in the area of the flash memory.

If protection code 01H is written in the security bit, the flash memory is in the protected state by security.

Therefore please do not write 01H in this address if you do not use the security function.

Refer to following table for the address of the security bit.

Flash memory size

Address of the security bit

MB90F347E

Embedded 1 Mbit Flash Memory

FE0001H

MB90F342E

MB90F349E

Embedded 2 Mbits Flash Memory

FC0001H

MB90F343E

Embedded 3 Mbits Flash Memory

F90001H

MB90F345E

Embedded 4 Mbits Flash Memory

F80001H

Port0 to Port3 outputs

might be unstable

Port0 to Port3 outputs = Hi-Z

Port0 to Port3

VCC

1/2VCC

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