Renesas RA Family
RA2 Quick Design Guide
R01AN6060EU0100 Rev.1.00
Page 10 of 44
Sep.14.21
Figure 4. Mode Setting Pin Level and Operating Mode
Note that USB boot mode is only available on devices that have the USB Full Speed peripheral, such as
RA2A1. For the RA2A1 MCU Group, USB boot mode doesn’t exist in 32-pin products.
A typical MCU boot mode circuit includes a jumper and a couple of resistors to allow selections to connect
the MD pin to VCC or Ground.
Figure 5. Typical Circuit for MCU Boot Mode Selection
4. Option Setting Memory
The option setting memory determines the state of the MCU after a reset. It is allocated to the configuration
setting area and the program flash area of the flash memory. The available methods of setting are different
for the two areas.
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. Additionally, when using binary files for
programming, the user must ensure that reserved areas of memory are not programmed due to the
addresses of the configuration setting area. 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 on without realizing it. This will
cause the debugger to have communications problems with the board.
The figure below shows the option setting memory area, which consists of the option function select registers
on RA2A1. The Option Setting Memory may be different for each device. Please consult MCU User’s Manual
for the specific device details.