MC68HC11PH8 Datasheet, PDF (31/264 Pages) Motorola, Inc – High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcomputer Unit

EXTAL
18 pF
2
(a) Common crystal connections
(32 to 38.4 kHz crystal)
M68HC11
22 MΩ
crystal
XTAL
390 kΩ
20 pF
(a) Common crystal connections
(500 to 2000 kHz crystal)
EXTAL
M68HC11
XTAL
10 MΩ
crystal
25 pF
25 pF
(b) External oscillator
connections
EXTAL
M68HC11
XTAL
External oscillator
NC
Note: capacitor values include all stray capacitance.
Note: all values of capacitance and resistance shown are approximate; exact values must be calculated knowing the crystal parameters
and the expected voltage and temperature ranges.
Figure 2-5 Oscillator connections (VDDSYN = 1, PLL enabled)
2.4
E clock output (E)
E is the output connection for the internally generated E clock. The signal from E is used as a
timing reference. The frequency of the E clock output is one quarter that of the input frequency at
the XTAL and EXTAL pins (except when the PLL is used as the clock source). When E clock output
is low, an internal process is taking place; when it is high, data is being accessed. All clocks,
including the E clock, are halted when the MCU is in STOP mode. The E clock output can be
turned off to reduce the effects of RFI (see Section 3.3.2.5).
MC68HC11PH8
PIN DESCRIPTIONS
TPG
MOTOROLA
2-5