s908ey8ad4cfjer Freescale Semiconductor, Inc, s908ey8ad4cfjer Datasheet - Page 245

• Manufacturer Part Number: s908ey8ad4cfjer
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

20.8 External Oscillator Characteristics
Freescale Semiconductor
External clock option
External crystal options
Crystal load capacitance
Crystal fixed capacitance
Crystal tuning capacitance
EXTSLOW = 1
EXTSLOW = 0
10. Not required for high-frequency crystals
1. V
2. Setting EXTCLKEN configuration option enables OSC1 pin for external clock square-wave input.
3. No more than 10% duty cycle deviation from 50%
4. EXTSLOW configuration option configures external oscillator for a slow speed crystal and sets the clock monitor circuits
5. Some modules may require a minimum frequency greater than dc for proper operation. See appropriate table for this
6. MCU speed derates from 32 MHz at V
7. Setting EXTCLKEN and EXTXTALEN configuration options enables OSC1 and OSC2 pins for external crystal option.
8. f
9. Crystal manufacturer’s value, see
With ICG clock disabled
With ICG clock enabled
EXTSLOW = 1
EXTSLOW = 0
Feedback bias resistor
Series resistor
Feedback bias resistor
Series resistor
of the ICG module to expect an external clock frequency that is higher/lower than the internal oscillator base frequency,
f
information.
EXTSLOW = 1
EXTSLOW = 0
f
f
f
Bus
INTOSC.
EXTOSC
EXTOSC
EXTOSC
DD
= (f
= 4.5 to 5.5 Vdc, V
EXTOSC
= 1 MHz
= 4 MHz
= 8 MHz
(4)
(4)
(9)
(9)(10)
(4)
(4)
/ 4) when external clock source is selected.
(2)(3)
Characteristic
(7)(8)
(9)
(9)
(9)
(9)
(9)
SS
= 0 Vdc, T
MC68HC908EY16 • MC68HC908EY8 Data Sheet, Rev. 10
(1)
Figure 8-3. Internal Clock Generator Block
A
DD
= –40°C to +135°C, unless otherwise noted
= 4.5 Vdc
Symbol
f
f
EXTOSC
EXTOSC
C
C
C
R
R
R
R
R
R
L
1
2
B
B
s
s
s
s
307.2 k
dc
30 k
Min
1 M
100
60
Diagram.
—
—
—
—
—
—
—
—
(5)
External Oscillator Characteristics
12.5
Typ
330
—
—
—
—
—
15
15
10
20
10
1
0
32 M
307.2 k
32 M
100 k
Max
8 M
470
—
—
—
—
—
—
—
—
(6)
(6)
Unit
MΩ
MΩ
kΩ
kΩ
kΩ
kΩ
Hz
Hz
pF
pF
pF
245