M16CSLASH1N datasheet(229/238 Pages) RENESAS

номер детали	M16C/1N

подробное описание детали	RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/10 SERIES

PDF	238 Pages

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229 / 238 page

Rev.1.00

Oct 20, 2004

page 217 of 222

M16C/1N Group

REJ090007-0100Z

20. Precautionary Notes in Using the Device

20.7 Noise

1. Bypass Capacitor between VCC and VSS Pins

Insert a bypass capacitor (at least 0.1 µF) between VCC and VSS pins as noise and latch-up

countermeasures. In addition, make sure that connecting lines are the shortest and widest pos-

sible.

2. Port Control Registers Data Read Error

During severe noise testing, mainly power supply system noise, and introduction of external noise,

the data of port related registers may changed. As a firmware countermeasure, it is recommended

to periodically re-set the port registers, port direction registers and pull-up control registers. How-

ever, you should fully examine before introducing the re-set routine as conflicts may be created

between this re-set routine and interrupt routines (i. e. ports are switched during interrupts).

3. CNVss pin wiring

CNVSS pin functions as a pin to change to shipment examination mode or flash memory rewrite

mode in the flash memory version.

In order to improve the pin tolerance to noise, insert a pull down resistance (about 5 kΩ) between

CNVss and Vss, and placed as close as possible to the CNVss pin.

M16C/1N датащи(PDF) 229 Page - Renesas Technology Corp