MC68HC908AS32A Datasheet, PDF (23/280 Pages) Freescale Semiconductor, Inc – Microcontrollers

Pin Assignments
PTC4 ₁
IRQ
2
RST
3
PTF0/TACH2
4
PTF1/TACH3
5
PTF2/TCH4
6
PTF3/TCH5
7
NC
8
BDRxD
9
BDTxD
10
NC
11
NC
12
PTE0/TxD
13
PTE1/RxD
14
PTE2/TACH0
15
PTE3/TACH1 ₁₆
48 ^NC
47
PTD3/ATD11
46
PTD2/ATD10
45
NC
44
NC
43
PTD1/ATD9
42
PTD0/ATD8
41
PTB7/ATD7
40
PTB6/ATD6
39
PTB5/ATD5
38
PTB4/ATD4
37
PTB3/ATD3
36
PTB2/ATD2
35
PTB1/ATD1
34
PTB0/ATD0
33 ^PTA7
Figure 1-3. 64-Pin QFP Assignments (Top View)
NOTE
The following pin descriptions are just a quick reference. For a more
detailed representation, see Chapter 13 Input/Output Ports.
1.4.1 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 shown in
Figure 1-4. 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.
MC68HC908AS32A Data Sheet, Rev. 2.0
Freescale Semiconductor
23