Datasheet
General Description
MC68HC908GP32 Data Sheet, Rev. 10
26 Freescale Semiconductor
Figure 1-4. 44-Pin QFP Pin Assignments
1.5 Pin Functions
Descriptions of the pin functions are provided here.
1.5.1 Power Supply Pins (V
DD
and V
SS
)
V
DD
and V
SS
are the power supply and ground pins. The MCU operates from a single power supply.
Fast signal transitions on MCU pins place high, short-duration current demands on the power supply. To
prevent noise problems, take special care to provide power supply bypassing at the MCU as Figure 1-5
shows. Place the C1 bypass capacitor as close to the MCU as possible. Use a high-frequency-response
ceramic capacitor for C1. C2 is an optional bulk current bypass capacitor for use in applications that
require the port pins to source high current levels.
44
34
43
42
41
40
39
38
37
36
35
1
2
3
4
5
6
7
8
9
10
11
13
14
15
16
17
18
19
20
21
22
33
32
31
30
29
28
27
26
25
24
12
23
RST
PTE0/TxD
PTE1/RxD
IRQ
PTC0
PTC1
PTC2
PTC3
PTC4
PTC5
PTC6
PTD5/T1CH1
PTD4/T1CH0
V
DD
V
SS
PTD3/SPSCK
PTD2/MOSI
PTD1/MISO
PTD0/SS
PTD6/T2CH0
PTD7/T2CH1
PTB0/AD0
PTB6/AD6
PTB7/AD7
V
DDAD
/V
REFH
V
SSAD
/V
REFL
PTA0/KBD0
PTB2/AD2
PTB3/AD3
PTB1/AD1
PTB4/AD4
PTB5/AD5
PTA4/KBD4
PTA5/KBD5
V
DDA
OSC1
OSC2
CGMXFC
V
SSA
PTA1/KBD1
PTA6/KBD6
PTA7/KBD7
PTA3/KBD3
PTA2/KBD2