XC68HC705JB3 Motorola, XC68HC705JB3 Datasheet - Page 16

• Manufacturer Part Number: XC68HC705JB3
• Description: MICROCONTROLLER
• Manufacturer: Motorola

GENERAL RELEASE SPECIFICATION
1.4
1.4.1 V
1.4.2 OSC1, OSC2
MOTOROLA
1-4
FUNCTIONAL PIN DESCRIPTION
The following paragraphs give a description of the general function of each pin
assigned in Figure 1-2.
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:
PB0/TCAP
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)
RESET
and V
PA0
PA1
PA2
PA3
PA4
PB1
PB2
IRQ
SS
is ground. The MCU operates from a single power supply.
SS
1
2
3
4
5
6
7
8
9
10
20-pin package
Figure 1-2. MC68HC05JB3 Pin Assignments
20
19
17
16
15
14
13
12
11
18
VDD
OSC1
OSC2
VSS
3.3V
D+
D–
PA7
PA6
PA5
GENERAL DESCRIPTION
November 5, 1998
PB0/TCAP
DD
RESET
and V
PC2
PC3
PA0
PA1
PA2
PA3
PA4
PB5
PB4
PB1
PB2
IRQ
1
2
3
4
5
6
7
8
9
10
11
12
13
14
SS
28-pin package
. V
DD
is the positive supply,
28
27
25
24
23
22
21
20
19
18
17
16
15
26
VDD
OSC1
OSC2
VSS
PC0/OCMP
PC1
3.3V
D+
D–
PB7
PB6
PA7
PA6
PA5
MC68HC05JB3
REV 1