MC68HC711E20CFS2 MOTOROLA [Motorola, Inc], MC68HC711E20CFS2 Datasheet - Page 25

• Manufacturer Part Number: MC68HC711E20CFS2
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

1.4.4 E-Clock Output (E)
1.4.5 Interrupt Request (IRQ)
M68HC11E Family — Rev. 5
MOTOROLA
CAUTION:
In all cases, use caution around the oscillator pins. Load capacitances shown in the
oscillator circuit are specified by the crystal manufacturer and should include all
stray layout capacitances.
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 fourth that
of the input frequency at the XTAL and EXTAL pins. 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. To
reduce RFI emissions, the E-clock output of most E-series devices can be disabled
while operating in single-chip modes.
The E-clock signal is always enabled on the MC68HC811E2.
The IRQ input provides a means of applying asynchronous interrupt requests to the
MCU. Either negative edge-sensitive triggering or level-sensitive triggering is
program selectable (OPTION register). IRQ is always configured to level-sensitive
triggering at reset. When using IRQ in a level-sensitive wired-OR configuration,
connect an external pullup resistor, typically 4.7 kΩ, to V
Freescale Semiconductor, Inc.
Figure 1-9. Common Parallel Resonant Crystal Connections
For More Information On This Product,
MCU
Figure 1-10. External Oscillator Connections
Go to: www.freescale.com
MCU
EXTAL
XTAL
EXTAL
General Description
XTAL
NC
10 MΩ
EXTERNAL OSCILLATOR
CRYSTAL
CMOS-COMPATIBLE
4 x E
4 x E
DD
C
C
L
L
.
General Description
Pin Descriptions
Data Sheet
25