mc68hc05jb4p Freescale Semiconductor, Inc, mc68hc05jb4p Datasheet - Page 16

• Manufacturer Part Number: mc68hc05jb4p
• Description: Mc68hc705jb4 Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

1.4
1.4.1 V
1.4.2 OSC1, OSC2
FUNCTIONAL PIN DESCRIPTION
The following paragraphs give a description of the general function of each pin
assigned in Fig. 1-2 and Fig. 1-3.
Power is supplied to the MCU through V
and V
Very fast 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 good high-frequency char-
acteristics that are positioned as close to the MCU as possible. Bypassing
requirements vary, depending on how heavily the MCU pins are loaded.
The OSC1 and OSC2 pins are the connections for the on-chip oscillator. The
OSC1 and OSC2 pins can accept the following sets of components:
The frequency, f
produce the internal operating frequency, f
3MHz, then the external oscillator frequency will be 6MHz. For LS USB 1.5MHz
DD
1. A crystal as shown in Figure 1-3 (a)
2. A ceramic resonator as shown in Figure 1-3 (a)
3. An external clock signal as shown in Figure 1-3 (b)
AND V
SS
is ground. The MCU operates from a single power supply.
SS
Figure 1-2. MC68HC05JB4 Pin Assignment
OSC
Freescale Semiconductor, Inc.
For More Information On This Product,
, of the oscillator or external clock source is divided by two to
PB0/ICAP1
PC2/AD2
PC1/AD1
PC0/AD0
PB4/AD5
PB3/AD4
RESET
PB2
PB1
PA0
PA1
PA2
PA3
IRQ
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1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
25
24
23
22
21
20
19
18
DD
17
16
15
26
OP
. If the internal operating frequency is
and V
PC3/AD3
PC4/VRH
PC5/VRL
3.3V
D+
D–
VDD
OSC1
OSC2
VSS
PA7
PA6
PA5
PA4/IRQ2
SS
. V
DD
is the positive supply,