High-Speed On-Chip Oscillator; Low-Speed On-Chip Oscillator - Renesas RL78/G1P Hardware User Manual

RL78/G1P

5.4.2 High-speed on-chip oscillator

The high-speed on-chip oscillator is incorporated in the RL78/G1P. The frequency can be selected from among 32, 24,
16, 12, 8, 6, 4, 3, 2, or 1 MHz by using the option byte (000C2H). Oscillation can be controlled by bit 0 (HIOSTOP) of the
clock operation status control register (CSC). The high-speed on-chip oscillator automatically starts oscillating after reset
release.

5.4.3 Low-speed on-chip oscillator

The low-speed on-chip oscillator is incorporated in the RL78/G1P.
The low-speed on-chip oscillator clock is used only as the watchdog timer. The low-speed on-chip oscillator clock
cannot be used as the CPU clock.
This clock operates when bit 4 (WDTON) of the option byte (000C0H) is set to 1.
If the watchdog timer operates in HALT, STOP or SNOOZE mode at WDSTBYON = 0, oscillation of the low-speed on-
chip oscillator is stopped. While the watchdog timer operates, the low-speed on-chip oscillator clock does not stop even if
the program freezes.
R01UH0895EJ0100 Rev.1.00
Nov 29, 2019
CHAPTER 5 CLOCK GENERATOR
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