MC68HC05P18A Datasheet, PDF (20/130 Pages) Freescale Semiconductor, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
General Description
RESET
1
IRQ
2
PA7
3
PA6
4
PA5
5
PA4
6
PA3
7
PA2
8
PA1
9
PA0
10
SDO/PB5
11
SDI/PB6
12
SCK/PB7
13
V_SS
14
28
V_DD
27
OSC1
26
OSC2
25
PD7/TCAP
24
TCMP
23
PD5/CKOUT
22
PC0
21
PC1
20
PC2
19
PC3/AD3
18
PC4/AD2
17
PC5/AD1
16
PC6/AD0
15
PC7/V_REFH
Figure 1-2. User Mode Pinout
1.5.1 Power Supply (V_DD and V_SS)
Power is supplied to the MCU through V_DD and V_SS . V_DD is connected
to a regulated +5-volt supply and V_SS is connected to ground.
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, take special care to provide good
power supply bypassing at the MCU. Use bypass capacitors with good
high-frequency characteristics and position them as close to the MCU as
possible. Bypassing requirements vary, depending on how heavily the
MCU pins are loaded.
1.5.2 Oscillator Pins (OSC1 and OSC2)
The OSC1 and OSC2 pins are the control connections for the on-chip
oscillator. The OSC1 and OSC2 pins can accept:
1. A crystal or ceramic resonator, as shown in Figure 1-3 (a)
2. An external clock signal, as shown in Figure 1-3 (b)
Technical Data
General Description
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MC68HC05P18A