General Description
Pin Assignments
MC68HC08AS32A — Rev. 1
Data Sheet
MOTOROLA
General Description
25
1.4.6 ADC High Reference Pin (V
REFH
)
V
REFH
is the high reference voltage for all analog-to-digital conversions. (See
Section 3. Analog-to-Digital Converter (ADC)
.)
1.4.7 Analog Ground Pin (V
SSA
/V
REFL
)
The V
SSA
/V
REFL
analog ground pin is used only for the ground connections for the
analog sections of the circuit and should be decoupled as per the V
SS
digital
ground pin. The analog sections consist of a clock generator module (CGM) and
an analog-to-digital converter (ADC). V
SSA
/V
REFL
is also the lower reference
supply for the ADC. (See
Section 5. Clock Generator Module (CGM)
and
Section 3. Analog-to-Digital Converter (ADC)
.)
1.4.8 External Filter Capacitor Pin (CGMXFC)
CGMXFC is an external filter capacitor connection for the CGM. (See
Section 5.
Clock Generator Module (CGM)
.)
1.4.9 Port A Input/Output (I/O) Pins (PTA7–PTA0)
PTA7–PTA0 are general-purpose bidirectional I/O port pins. (See
Section 12.
Input/Output (I/O) Ports
.)
1.4.10 Port B I/O Pins (PTB7/ATD7–PTB0/ATD0)
Port B is an 8-bit special function port that shares all eight pins with the
analog-to-digital converter (ADC). (See
Section 3. Analog-to-Digital Converter
(ADC)
and
Section 12. Input/Output (I/O) Ports
.)
1.4.11 Port C I/O Pins (PTC4–PTC0)
PTC4
–
PTC3 and
PTC1
–
PTC0 are general-purpose bidirectional I/O port pins.
PTC2/MCLK is a special function port that shares its pin with the system clock.
(See
Section 12. Input/Output (I/O) Ports
.)
1.4.12 Port D I/O Pins (PTD6/ATD14/TCLKA–PTD0/ATD8)
Port D is a 7-bit special function port that shares all of its pins with the
analog-to-digital converter module (ADC) and one of its pins with the timer
interface module (TIM). (See
Section 16. Timer Interface (TIM)
,
Section 3.
Analog-to-Digital Converter (ADC)
, and
Section 12. Input/Output (I/O) Ports
.)
1.4.13 Port E I/O Pins (PTE7/SPSCK–PTE0/TxD)
Port E is an 8-bit special function port that shares two of its pins with the timer
interface module (TIM), four of its pins with the serial peripheral interface module
F
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n
.