Renesas RL78/G1H, User Manual

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RL78/G1H CHAPTER 6 CLOCK GENERATOR
R01UH0575EJ0120 Rev. 1.20 Page 98 of 920
Dec 22, 2016
(3) Low-speed on-chip oscillator (Low-speed OCO)
This circuit oscillates a clock of f
IL
= 15 kHz (TYP.).
The low-speed on-chip oscillator clock cannot be used as the CPU clock.
Only the following peripheral hardware runs on the low-speed on-chip oscillator clock.
• Watchdog timer
• Real-time clock
• 12-bit interval timer
• Timer RJ
This clock operates when bit 4 (WDTON) of the option byte (000C0H), bit 4 (WUTMMCK0) of the subsystem
clock supply mode control register (OSMC), or both are set to 1.
However, if WDTON = 1, WUTMMCK0 = 0, and bit 0 (WDSTBYON) of the option byte (000C0H) is 0, the low-
speed on-chip oscillator stops oscillation when the HALT or STOP instruction is executed.
Caution The low-speed on-chip oscillator clock (f
IL
) can only be selected as the real-time clock count
clock when the fixed-cycle interrupt function is used.
Remark f
X
: X1 clock oscillation frequency
f
IH
: High-speed on-chip oscillator clock frequency
f
EX
: External main system clock frequency
f
XT
: XT1 clock oscillation frequency
f
EXS
: External subsystem clock frequency
f
IL
: Low-speed on-chip oscillator frequency