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RL78/G1A CHAPTER 24 OPTION BYTE
24.4 Setting of Option Byte
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The user option byte and on-chip debug option byte can be set using the link option, in addition to describing to the
source. When doing so, the contents set by using the link 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
DB 85H ; Enables on-chip debug operation, does not erase flash memory
data when security ID authorization fails
Jul 04, 2013
When the boot swap function is used during self programming, 000C0H to 000C3H is switched to 010C0H to 010C3H.
Describe to 010C0H to 010C3H, therefore, the same values as 000C0H to 000C3H as follows.
OPT2 CSEG AT 010C0H
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
10
/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 main voltage) mode as the flash operation mode
and 1 MHz as the frequency of the high-speed on-chip oscillator
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. To specify the option byte to 010C0H to 010C3H in order to
use the boot swap function, use the relocation attribute AT to specify an absolute address.
R01UH0305EJ0200 Rev.2.00 799