568
Digital Electronics
A/D
Converter
D/A
Converter
Parallel
Ports
Serial
Ports
Counters/
Timers
Central
Processing
Unit
Memory
SFRs
From
Sensors
To Actuators
Keyboard,
Displays
etc.
Figure 14.3 Inside the microcontroller.
Clock
Free-Running
Counter
Timer Input
System
Timer Output
System
Figure 14.4 Timer subsystem.
14.2.1 Central Processing Unit (CPU)
The central processing unit processes the program. It executes the instructions stored in the program
memory pointed to by the program counter in synchronization with the clock signal. The processor
complexity could vary from simple eight-bit processors to sophisticated 32-bit or even 64-bit processors.
Some common microcontrollers using eight-bit processors include 68HC11 (Freescale Semiconductor
– earlier part of Motorola), the 80C51 family of microcontrollers (Intel and Dallas Semiconductor),
Zilog-eZ8 and Zilog-eZ80 (Zilog) and XC800 (Infineon). Examples of microcontrollers using 16-bit
processors include the 8096 family (Intel), 68HC12 and 68HC16 (Freescale Semiconductor), the
F2MC family (Fujitsu) and the XC166 family (Infineon). Examples of microcontrollers using 32bit processors include 683XX, MPC 860 (PowerQUICC), MPC 8240/8250 (PowerQUICC-II) and
MPC 8540/8555/8560 (PowerQUICC-III) (all from Freescale Semiconductor), the TRICORE family
(Infineon) and the FR/FR-V family (Fujitsu).
Digital Electronics
A/D
Converter
D/A
Converter
Parallel
Ports
Serial
Ports
Counters/
Timers
Central
Processing
Unit
Memory
SFRs
From
Sensors
To Actuators
Keyboard,
Displays
etc.
Figure 14.3 Inside the microcontroller.
Clock
Free-Running
Counter
Timer Input
System
Timer Output
System
Figure 14.4 Timer subsystem.
14.2.1 Central Processing Unit (CPU)
The central processing unit processes the program. It executes the instructions stored in the program
memory pointed to by the program counter in synchronization with the clock signal. The processor
complexity could vary from simple eight-bit processors to sophisticated 32-bit or even 64-bit processors.
Some common microcontrollers using eight-bit processors include 68HC11 (Freescale Semiconductor
– earlier part of Motorola), the 80C51 family of microcontrollers (Intel and Dallas Semiconductor),
Zilog-eZ8 and Zilog-eZ80 (Zilog) and XC800 (Infineon). Examples of microcontrollers using 16-bit
processors include the 8096 family (Intel), 68HC12 and 68HC16 (Freescale Semiconductor), the
F2MC family (Fujitsu) and the XC166 family (Infineon). Examples of microcontrollers using 32bit processors include 683XX, MPC 860 (PowerQUICC), MPC 8240/8250 (PowerQUICC-II) and
MPC 8540/8555/8560 (PowerQUICC-III) (all from Freescale Semiconductor), the TRICORE family
(Infineon) and the FR/FR-V family (Fujitsu).