MC908KX2MDWE Datasheet, PDF (20/210 Pages) Freescale Semiconductor, Inc – High-performance M68HC08 architecture, Fully upward-compatible object code with M6805, M146805, and M68HC05 Families

General Description
1.4 Pin Assignments
Figure 1-2 shows the pin assignments for MC68HC908KX8.
V_SS 1
PTA1/KBD1 2
PTA0/KBD0 3
IRQ1 4
PTB0/AD0 5
PTB1/AD1 6
PTB2/AD2 7
PTB3/AD3 8
16 V_DD
15 PTA4/KBD4
14 PTA3/KBD3/TCH1
13 PTA2/KBD2/TCH0
12 PTB4/RxD
11 PTB5/TxD
10 PTB6/(OSC1)
9 PTB7/(OSC2)/RST
Figure 1-2. PDIP and SOIC Pin Assignments
1.4.1 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 1-3. Place the bypass capacitors as close to the MCU power pins as possible. Use high-frequency
response ceramic capacitors for C_Bypass. C_Bulk are optional bulk current bypass capacitors for use in
applications that require the port pins to source high-current levels.
MCU
V_DD
V_SS
C_Bypass
0.1 µF
+
C_Bulk
V_DD
Note: Component values shown represent typical applications.
Figure 1-3. Power Supply Bypassing
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 Data Sheet, Rev. 2.1
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Freescale Semiconductor