Datasheet

Pin Functions
MC68HC908GZ60 • MC68HC908GZ48 • MC68HC908GZ32 Data Sheet, Rev. 6
Freescale Semiconductor 29
Figure 1-5. Power Supply Bypassing
1.5.2 Oscillator Pins (OSC1 and OSC2)
OSC1 and OSC2 are the connections for an external crystal, resonator, or clock circuit. See Chapter 4
Clock Generator Module (CGM).
1.5.3 External Reset Pin (RST)
A low on the RST pin forces the MCU to a known startup state. RST is bidirectional, allowing a reset of
the entire system. It is driven low when any internal reset source is asserted. This pin contains an internal
pullup resistor. See Chapter 15 System Integration Module (SIM).
1.5.4 External Interrupt Pin (IRQ)
IRQ is an asynchronous external interrupt pin. This pin contains an internal pullup resistor. See
Chapter 8 External Interrupt (IRQ).
1.5.5 CGM Power Supply Pins (V
DDA
and V
SSA
)
V
DDA
and V
SSA
are the power supply pins for the analog portion of the clock generator module (CGM).
Decoupling of these pins should be as per the digital supply. See Chapter 4 Clock Generator Module
(CGM).
1.5.6 External Filter Capacitor Pin (CGMXFC)
CGMXFC is an external filter capacitor connection for the CGM. See Chapter 4 Clock Generator Module
(CGM).
1.5.7 ADC Power Supply/Reference Pins (V
DDAD
/V
REFH
and V
SSAD
/V
REFL
)
V
DDAD
and V
SSAD
are the power supply pins to the analog-to-digital converter (ADC). V
REFH
and V
REFL
are the reference voltage pins for the ADC. V
REFH
is the high reference supply for the ADC, and by default
the V
DDAD
/V
REFH
pin should be externally filtered and connected to the same voltage potential as V
DD
.
MCU
V
DD
C2
C1
0.1 μF
V
SS
V
DD
+
Note: Component values shown represent typical applications.