MC68HC908JK3ECP Freescale Semiconductor, MC68HC908JK3ECP Datasheet - Page 69

• Manufacturer Part Number: MC68HC908JK3ECP
• Description: IC MCU 4K FLASH 8MHZ 20-DIP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908JK3ECP

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Peripherals: LED, LVD, POR, PWM
• Number Of I /o: 15
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.3 V
• Data Converters: A/D 12x8b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Connectivity: -

6.4 I/O Signals
The following paragraphs describe the oscillator I/O signals.
6.4.1 Crystal Amplifier Input Pin (OSC1)
OSC1 pin is an input to the crystal oscillator amplifier or the input to the RC oscillator circuit.
6.4.2 Crystal Amplifier Output Pin (OSC2/PTA6/RCCLK)
For the X-tal oscillator device, OSC2 pin is the output of the crystal oscillator inverting amplifier.
For the RC oscillator device, OSC2 pin can be configured as a general purpose I/O pin PTA6, or the
output of the internal RC oscillator clock, RCCLK.
6.4.3 Oscillator Enable Signal (SIMOSCEN)
The SIMOSCEN signal comes from the system integration module (SIM) and enables/disables the X-tal
oscillator circuit or the RC-oscillator.
6.4.4 X-tal Oscillator Clock (XTALCLK)
XTALCLK is the X-tal oscillator output signal. It runs at the full speed of the crystal (f
directly from the crystal oscillator circuit.
and OSC2 and may not represent the actual circuitry. The duty cycle of XTALCLK is unknown and may
depend on the crystal and other external factors. Also, the frequency and amplitude of XTALCLK can be
unstable at start-up.
6.4.5 RC Oscillator Clock (RCCLK)
RCCLK is the RC oscillator output signal. Its frequency is directly proportional to the time constant of the
external R and C.
the actual circuitry.
6.4.6 Oscillator Out 2 (2OSCOUT)
2OSCOUT is same as the input clock (XTALCLK or RCCLK). This signal is driven to the SIM module and
is used to determine the COP cycles.
6.4.7 Oscillator Out (OSCOUT)
The frequency of this signal is equal to half of the 2OSCOUT, this signal is driven to the SIM for generation
of the bus clocks used by the CPU and other modules on the MCU. OSCOUT will be divided again in the
SIM and results in the internal bus frequency being one fourth of the XTALCLK or RCCLK frequency.
Freescale Semiconductor
MC68HRC908JL3E/JK3E/JK1E
MC68HC908JL3E/JK3E/JK1E
Figure 6-2
Device
shows only the logical relation of RCCLK to OSC1 and may not represent
MC68HC908JL3E Family Data Sheet, Rev. 4
Figure 6-1
Oscillator
X-tal
RC
shows only the logical relation of XTALCLK to OSC1
PTA6EN = 0: RCCLK output
PTA6EN = 1: PTA6 I/O
Controlled by PTA6EN bit in PTAPUER ($0D)
OSC2 pin function
Inverting OSC1
XCLK
) and comes
I/O Signals
69