R5F21133DFP RENESAS [Renesas Technology Corp], R5F21133DFP Datasheet - Page 209

• Manufacturer Part Number: R5F21133DFP
• Description: 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY/R8C/Tiny SERIES
• Manufacturer: RENESAS [Renesas Technology Corp]

R8C/13 Group
Rev.1.20
REJ09B0111-0120
19.8 Noise
(1) Bypass Capacitor between V
(2) Port Control Registers Data Read Error
(3) CNVss Pin Wiring
Insert a bypass capacitor (at least 0.1 µF) between V
noise and latch-up. The connecting wires must be the shortest and widest possible.
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 reset the port registers, port direction registers and pull-up control registers. However, you
should fully examine before introducing the reset routine as conflicts may be created between this
reset routine and interrupt routines (i. e. ports are switched during interrupts).
In order to improve the pin tolerance to noise, insert a pull down resistance (about 5 k ) between
CNVss and Vss, and placed as close as possible to the CNVss pin.
Jan 27, 2006
page 198 of 205
CC
and V
SS
Pins
CC
and V
SS
pins as the countermeasures against
19. Usage Notes