MC68HC908LB8CPE Freescale Semiconductor, MC68HC908LB8CPE Datasheet - Page 126

• Manufacturer Part Number: MC68HC908LB8CPE
• Description: IC MCU 8K FLASH 8MHZ 20DIP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908LB8CPE

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Peripherals: LVR, POR, PWM
• Number Of I /o: 18
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 7x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Connectivity: -

Oscillator Module (OSC)
13.3.3 XTAL Oscillator
The XTAL oscillator circuit is designed for use with an external crystal or ceramic resonator to provide an
accurate clock source. In this configuration, the OSC2 pin is dedicated to the external crystal circuit. The
OSC2EN bit in the port C pullup enable register has no effect when this clock mode is selected.
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:
13.3.4 RC Oscillator
The RC oscillator circuit is designed for use with external R to provide a clock source with tolerance less
than 25%. See
In its typical configuration, the RC oscillator requires two external components, one R and one C. In the
MC68HC908LB8, the capacitor is internal to the chip. The R value should have a tolerance of 1% or less,
to obtain a clock source with less than 25% tolerance. The oscillator configuration uses one component,
R
In this configuration, the OSC2 pin can be left in the reset state as PTC1. Or, the OSC2EN bit in the port
C pullup enable register can be set to enable the OSC2 function on the pin without affecting the clocks.
126
EXT
Figure
•
•
•
•
•
.
Crystal, X
Fixed capacitor, C
Tuning capacitor, C
Feedback resistor, R
Series resistor, R
13-2. This figure shows only the logical representation of the internal components and may not
The series resistor (R
oscillator guidelines and may not be required for all ranges of operation,
especially with high frequency crystals. Refer to the crystal manufacturer’s
data for more information.
Figure
1
13-3.
S
1
(optional)
2
B
(can also be a fixed capacitor)
S
MC68HC908LB8 Data Sheet, Rev. 1
) is included in the diagram to follow strict Pierce
NOTE
Freescale Semiconductor