mc908jl16 Freescale Semiconductor, Inc, mc908jl16 Datasheet - Page 64

• Manufacturer Part Number: mc908jl16
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Oscillator (OSC)
OSCSEL — Oscillator Select Bit
Bits 6–0 — Should be left as logic 1’s.
5.2.1 XTAL Oscillator
The XTAL oscillator circuit is designed for use with an external crystal or ceramic resonator to provide
accurate clock source.
In its typical configuration, the XTAL oscillator is connected in a Pierce oscillator configuration, as shown
in
represent actual circuitry. The oscillator configuration uses five components:
The series resistor (R
be required for all ranges of operation, especially with high frequency crystals. Refer to the crystal
manufacturer’s data for more information.
5.2.2 RC Oscillator
The RC oscillator circuit is designed for use with external resistor and capacitor to provide a clock source
with tolerance less than 10%. See
In its typical configuration, the RC oscillator requires two external components, one R and one C.
Component values should have a tolerance of 1% or less, to obtain a clock source with less than 10%
tolerance. The oscillator configuration uses two components:
64
Figure
OSCSEL selects the oscillator type for the MCU. The erased or unprogrammed state of this bit is
logic 1, selecting the crystal oscillator option. This bit is unaffected by reset.
•
•
•
•
•
•
•
1 = Crystal oscillator
0 = RC oscillator
Crystal, X
Fixed capacitor, C
Tuning capacitor, C
Feedback resistor, R
Series resistor, R
C
R
EXT
EXT
5-2. This figure shows only the logical representation of the internal components and may not
Non-volatile FLASH register; write by programming.
Address:
When Crystal oscillator is selected, the OSC2/RCCLK/PTA6/KBI6 pin is
used as OSC2; other functions such as PTA6/KBI6 will not be available.
Erased:
Reset:
Read:
Write:
1
S
OSCSEL
) is included in the diagram to follow strict Pierce oscillator guidelines and may not
$FFD0
Bit 7
S
R
1
1
(optional)
2
B
(can also be a fixed capacitor)
Figure 5-1. Mask Option Register (MOR)
= Reserved
R
6
1
Figure
MC68HC908JL16 Data Sheet, Rev. 1.1
5-3.
R
5
1
NOTE
Unaffected by reset
R
4
1
R
3
1
R
2
1
R
1
1
Freescale Semiconductor
Bit 0
R
1