Datasheet
RL78/L12 CHAPTER 25 OPTION BYTE
R01UH0330EJ0200 Rev.2.00 797
Dec 13, 2013
CHAPTER 25 OPTION BYTE
25.1 Functions of Option Bytes
Addresses 000C0H to 000C3H of the flash memory of the RL78/L12 form an option byte area.
Option bytes consist of user option byte (000C0H to 000C2H) and on-chip debug option byte (000C3H).
Upon power application or resetting and starting, an option byte is automatically referenced and a specified function is
set. When using the product, be sure to set the following functions by using the option bytes.
For the bits to which no function is allocated, be sure to set the value specified in this manual.
25.1.1 User option byte (000C0H to 000C2H)
(1) 000C0H
Operation of watchdog timer
• Operation is stopped or enabled in the HALT or STOP mode.
Setting of overflow time of watchdog timer
Operation of watchdog timer
• Operation is stopped or enabled.
Setting of window open period of watchdog timer
Setting of interval interrupt of watchdog timer
• Used or not used
(2) 000C1H
Setting of LVD operation mode
• Interrupt & reset mode.
• Reset mode.
• Interrupt mode.
• LVD off (by controlling the externally input reset signal on the RESET pin)
Setting of LVD detection level (V
LVDH, VLVDL, VLVD)
Caution After power is supplied, the reset state must be retained until the operating voltage becomes in the
range defined in 30.4 or 31.4 AC Characteristics. This is done by utilizing the voltage detection circuit
or controlling the externally input reset signal. After the power supply is turned off, this LSI should be
placed in the STOP mode, or placed in the reset state by utilizing the voltage detection circuit or
controlling the externally input reset signal, before the voltage falls below the operating range. The
range of operating voltage varies with the setting of the user option byte (000C2H).
(3) 000C2H
Setting of flash operation mode
• LV (low voltage main) mode
• LS (low speed main) mode
• HS (high speed main) mode
Setting of the frequency of the high-speed on-chip oscillator
• Select from 24 MHz/16 MHz/12 MHz/8 MHz/6 MHz/4 MHz/3 MHz/2 MHz/1 MHz (TYP.).
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