GENERAL RELEASE SPECIFICATION
August 27, 1998
1.5
PIN ASSIGNMENTS
The MC68HC05SB7 is available in 28-pin SSOP package. The pin assignments
are shown in Figure 1-2.
1
28
27
26
25
24
23
22
21
20
19
18
17
16
15
PA7/SDA1
PA6/SCL1
PC7
RESET
2
PA5/SDA0
PA4/SCL0
PA3/PWM3
PA2/PWM2
PA1/PWM1
PA0/PWM0
ESV
3
4
PC6
5
PC5
6
PC4
7
IRQ/VPP
PB1/TCAP
PB2/CS0 (OSC1)
PB3/CS1 (OSC2)
PB4/AN3
PB5/AN2
PB6/AN1
PB7/AN0
8
9
VM
10
11
12
13
14
CSA
TM
CAP(ADC)
V
SS
V
DD
Figure 1-2. MC68HC05SB7 Pin Assignments
1.6
FUNCTIONAL PIN DESCRIPTION
The following paragraphs give a description of the general function of each pin.
1.6.1 V , V
DD SS
Power is supplied to the MCU through V
and V . V
is the positive supply,
DD
SS DD
and V is ground. The MCU operates from a single power supply.
SS
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.
1.6.2 OSC1, OSC2
When selected by a mask option, the OSC1 and OSC2 pins are the connections
for the external pin oscillator (EPO). The OSC1 and OSC2 pins can accept the fol-
lowing sets of components:
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).
MOTOROLA
1-4
GENERAL DESCRIPTION
MC68HC05SB7
REV 2.1
FREESCALE [ Freescale ]
