MC68HC05X16 Datasheet, PDF (39/232 Pages) Freescale Semiconductor, Inc – High-density complementary metal oxide semiconductor HCMOS) microcontroller unit

Freescale Semiconductor, Inc.
2.3.12.4 Oscillator division
The external oscillator can run up to 22MHz. For this reason an additional clock predivider is
2
provided; its division ratio is selected via a mask option (see Section 1.2). This allows a CPU clock
two, four, eight or ten times slower than the external clock, provided that SLOW mode has not been
entered. If the device is in SLOW mode, a further divide-by-16 oscillator predivider reduces the
CPU clock frequency to a frequency 32, 64, 128 or 160 times slower than the oscillator clock. The
MCAN is directly clocked with the external oscillator frequency divided by two. A block diagram of
the oscillator divider circuit is given in Figure 2-7.
OSC1
pin
OSC2
pin
Mask option
÷ 2 ^{MCAN clock}
MCAN module
Oscillator
÷1, ÷2,
÷4, or ÷5
÷2
f_OSC/2, /4, /8 or /10
÷ 16
f_OSC/32, /64,
/128 or /160
SM bit
Control logic
Main internal clock
Figure 2-7 Oscillator divider block diagram
2.3.13 PLMA
The PLMA pin is the output of pulse length modulation converter A.
2.3.14 PLMB
The PLMB pin is the output of pulse length modulation converter B.
MC68HC05X16 MODES OF OPERATION AND PIN DESCRIPTIONS
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