mc68hc11f1cpu3 Freescale Semiconductor, Inc, mc68hc11f1cpu3 Datasheet - Page 18

• Manufacturer Part Number: mc68hc11f1cpu3
• Description: Mc68hc11f1 Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

2-4
The XTAL pin is normally left unterminated when an external CMOS compatible clock
is connected to the EXTAL pin. However, a 10 k
from the XTAL output to ground can be used to reduce RFI noise emission.
The XTAL output is normally used to drive a crystal. The XTAL output can be buffered
with a high-impedance buffer, or it can be used to drive the EXTAL input of another
M68HC11 device. Refer to Figure 2-6 .
In all cases, use caution when designing circuitry associated with the oscillator pins.
Load capacitances shown in the oscillator circuits include all stray layout capacitanc-
es. Refer to Figure 2-4, Figure 2-5, and Figure 2-6.
FIRST
MCU
EXTAL
*
XTAL
Values include all stray capacitances.
Figure 2-5 External Oscillator Connections
Figure 2-6 One Crystal Driving Two MCUs
Figure 2-4 Common Crystal Connections
Freescale Semiconductor, Inc.
10M
For More Information On This Product,
MCU
MCU
CRYSTAL
4 x E
EXTAL
*
XTAL
Go to: www.freescale.com
Values include all stray capacitances.
EXTAL
XTAL
PIN DESCRIPTIONS
10M
25 pF
25 pF
10 k – 100 k
NC OR
LOAD
*
*
CRYSTAL
4 x E
CMOS-COMPATIBLE
EXTERNAL
OSCILLATOR
to 100 k
10 k – 100 k
25 pF
25 pF
NC OR
LOAD
220
*
*
load resistor connected
EXTAL
XTAL
TECHNICAL DATA
SECOND
MCU
MC68HC11F1