MC68HC705SR3CP Freescale Semiconductor, MC68HC705SR3CP Datasheet - Page 23

• Manufacturer Part Number: MC68HC705SR3CP
• Description: IC MCU 3.75K 2.1MHZ OTP 40-DIP
• Manufacturer: Freescale Semiconductor
• Series: HC05r

Specifications of MC68HC705SR3CP

• Core Processor: HC05
• Core Size: 8-Bit
• Speed: 4MHz
• Peripherals: LED, POR
• Number Of I /o: 32
• Program Memory Size: 3.75KB (3.75K x 8)
• Program Memory Type: OTP
• Ram Size: 192 x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 4x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Connectivity: -

The external oscillator clock frequency, f
frequency, f
2.2.1
The circuit in Figure 2-1(a) shows a typical oscillator circuit for an AT-cut, parallel resonant crystal.
The crystal manufacturer’s recommendations should be followed, as the crystal parameters
determine the external component values required to provide maximum stability and reliable
start-up. The load capacitance values used in the oscillator circuit design should include all stray
capacitances. The crystal and components should be mounted as close as possible to the pins for
start-up stabilization and to minimize output distortion. An external start-up resistor of
approximately 10MΩ is needed between OSC1 and OSC2 for the crystal type oscillator.
2.2.2
An external clock from another CMOS-compatible device can be connected to the OSC1 input,
with the OSC2 input not connected, as shown in Figure 2-1(b).
MC68HC05SR3
(a) Crystal or ceramic resonator connections
(c) RC option 1 - external resistor
OP
.
Crystal Oscillator
External Clock
Unconnected
OSC1
OSC1
10% to 25% accurate
25p
10MΩ
MCU
MCU
Figure 2-1 Oscillator Connections
OSC2
OSC2
25p
PIN DESCRIPTIONS
R
OSC
V
, is divided by two to produce the internal operating
DD
(b) External clock source connection
(d) RC option 2 - internal resistor
OSC1
OSC1
25% to 50% accurate
MCU
MCU
External Clock
OSC2
OSC2
Unconnected
Freescale
TPG
2-3
2