Renesas RA Series Quick Design Guide

Renesas RA Family RA4 Quick Design Guide
R01AN5988EU0100 Rev.1.00 Page 13 of 51
Jul.21.21
The registers are detailed in the “Option Setting Memory” chapter in the Hardware User’s Manual.
The flash option registers occupy space in the code flash memory map. Although the registers are located in
a portion of the flash memory that was reserved on the RA MCUs, it is possible that some customers may
store data in these locations inadvertently. The user must check to ensure that no unwanted data is
written to these locations or else unexpected behavior of the chip may result. For instance, settings in the
flash option registers can enable the Independent Watchdog Timer (IWDT) immediately after reset. If data
stored in program ROM inadvertently overlaps the Option Setting Memory register, it is possible to turn on
the IWDT without realizing it. This will cause the debugger to have communications problems with the board.
The figure below shows the option setting memory, which consists of the option function select registers on
RA4M3, which is a Arm Cortex-M33 device. The Option Setting Memory may be different for each device.
Please consult MCU User’s Manual for the specific device details.

Renesas RA Series Specifications

General

Brand	Renesas
Model	RA Series
Category	Microcontrollers
Language	English