Datasheet

Oscillator Module (OSC)
Low Power Modes
MC68HC908QY4•MC68HC908QT4•MC68HC908QY2•MC68HC908QT2•MC68HC908QY1•MC68HC908QT1
MOTOROLA Oscillator Module (OSC) 109
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8.5.5 RC Oscillator Clock (RCCLK)
RCCLK is the RC oscillator output signal. Its frequency is directly
proportional to the time constant of external R and internal C. Figure 8-2
shows only the logical relation of RCCLK to OSC1 and may not
represent the actual circuitry.
8.5.6 Internal Oscillator Clock (INTCLK)
INTCLK is the internal oscillator output signal. Its nominal frequency is
fixed to 12.8 MHz, but it can be also trimmed using the oscillator
trimming feature of the OSCTRIM register (see 8.4.1.1 Internal
Oscillator Trimming).
8.5.7 Oscillator Out 2 (BUSCLKX4)
BUSCLKX4 is the same as the input clock (XTALCLK, RCCLK, or
INTCLK). This signal is driven to the SIM module and is used to
determine the COP cycles.
8.5.8 Oscillator Out (BUSCLKX2)
The frequency of this signal is equal to half of the BUSCLKX4, this signal
is driven to the SIM for generation of the bus clocks used by the CPU
and other modules on the MCU. BUSCLKX2 will be divided again in the
SIM and results in the internal bus frequency being one fourth of either
the XTALCLK, RCCLK, or INTCLK frequency.
8.6 Low Power Modes
The WAIT and STOP instructions put the MCU in low-power
consumption standby modes.