Datasheet

Pin Functions
MC68HC908GP32 Data Sheet, Rev. 10
Freescale Semiconductor 27
Figure 1-5. Power Supply Bypassing
1.5.2 Oscillator Pins (OSC1 and OSC2)
The OSC1 and OSC2 pins are the connections for the on-chip oscillator circuit. See Chapter 5 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 14 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 9 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).
Connect the V
DDA
pin to the same voltage potential as V
DD
, and the V
SSA
pin to the same voltage
potential as V
SS
. Decoupling of these pins should be as per the digital supply. See Chapter 5 Clock
Generator Module (CGM)
1.5.6 External Filter Capacitor Pin (CGMXFC)
CGMXFC is an external filter capacitor connection for the CGM. See Chapter 5 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 for the analog-to-digital converter (ADC). Connect the V
DDAD
pin to the same voltage potential as V
DD
, and the V
SSAD
pin to the same voltage potential as V
SS
.
MCU
V
DD
C2
C1
0.1 µF
V
SS
V
DD
+
NOTE: Component values shown
represent typical applications.