Renesas RL78 Series Application Note

RL78 Family VDE Certified IEC60730/60335 Self Test Library
R01AN0749EG0201 Rev.2.01 Page 30 of 50
Mar 04, 2014
3.4 System Clock Verification
If a fault is detected with the system clock then the aim of should be to get to a safe operating point, where system
can be controlled using a different known clock.
3.4.1 Power-Up
The system clock should be verified at power on or reset. It may be necessary to test the clock once the
system has been initialised and the full system clock frequency has been set and stabilised.
3.4.2 Periodic
Periodic testing of the system clock can be made at any time where the application has the time available.
This is because the reference clock is typically much slower that the system clock in order to increase the
accuracy of the clock measurement.
(i.e. System clock = 32 MHZ, Reference clock = 15 KHz)

Renesas RL78 Series Specifications

General

Core	RL78
CPU Clock Speed	Up to 32 MHz
Flash Memory	Up to 512 KB
RAM	Up to 32 KB
Operating Voltage	1.6 V to 5.5 V
Low Power Modes	HALT, STOP, SNOOZE
CPU Architecture	16-bit
Temperature Range	-40°C to +85°C
Package	LQFP
Timers	16-bit timers
Communication Interfaces	UART, I2C, LIN
A/D Converter	12-bit