
General Description
MCU Structure
MC68HC05K3 — Rev. 5
Technical Data
General Description
Figure 1-3. Pin Assignments for 20-Pin SSOP
1.6 MCU Structure
The overall block diagram of the MC68HC05K3 is shown in Figure 1-4.
1.7 Functional Pin Description
The following paragraphs give a description of the general function of
each pin.
1.7.1 VDD and VSS
Power is supplied to the MCU through VDD and VSS. VDD is the positive
supply and VSS is ground. The MCU operates from a single power
supply.
Rapid signal transitions occur on the MCU pins. The short rise and fall
times place very high short-duration current demands on the power
supply. To prevent noise problems, special care should be taken to
provide good power supply bypassing at the MCU by using bypass
capacitors with high-frequency characteristics that are positioned as
close to the MCU as possible.
RESET
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
PB1/OSC3
PB0
IRQ
N/C
PA0
PA1
PA2
PA3
PA4
PA5
PA6
PA7
N/C
VDD
VSS
OSC2
OSC1
20-P
IN
SSOP
PAC
KA
GE
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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ARCHIVED
BY
FREESCALE
SEMICONDUCT
OR,
INC.
2006