Datasheet

RL78/L12 CHAPTER 25 OPTION BYTE
R01UH0330EJ0200 Rev.2.00 804
Dec 13, 2013
25.4 Setting of Option Byte
The user option byte and on-chip debug option byte can be set using the assembler linker option, in addition to
describing to the source. When doing so, the contents set by using the linker option take precedence, even if descriptions
exist in the source, as mentioned below.
A software description example of the option byte setting is shown below.
OPT CSEG OPT_BYTE
DB 36H ; Does not use interval interrupt of watchdog timer,
; Enables watchdog timer operation,
; Window open period of watchdog timer is 50%,
; Overflow time of watchdog timer is 2
9
/fIL,
; Stops watchdog timer operation during HALT/STOP mode
DB 1AH ; Select 1.63 V for V
LVDL
; Select rising edge 1.77 V, falling edge 1.73 V for V
LVDH
; Select the interrupt & reset mode as the LVD operation mode
DB 2DH ; Select the LV (low voltage main) mode as the flash operation mode
and 1 MHz as the frequency of the high-speed on-chip oscillator clock
DB 85H ; Enables on-chip debug operation, does not erase flash memory
data when security ID authorization fails
Caution To specify the option byte by using assembly language, use OPT_BYTE as the relocation attribute
name of the CSEG pseudo instruction.