Block Diagram of Microcontroller
ALU
(ArithmeHc Logic Unit)
Registers
(Accumulator &
General Purpose)
I RAM
I ROM
[ CPU
Interrupt
Circuit
Timer / Counter
I
I
]
0
Program Counter
(PC)
Stack Pointer
(SP)
Clock
Circuit
Input / Output Ports
CLASSIFICATION OF MICROCON'fROJ.J.ER
Bits Memory Instruction Set Architecture
0
• CISC • Von-neumann
• 4 bit • External Memory
• 8 bit • Embedded Memory •
RISC • Harvard
• 16 bit Family
• 32 bit
t l I I I I l
8051 Motorola PIC Texas National
ARM Other
I I I I
INTEL Atmel Dallas Phillips
Siemens
CLASmf'ICATION ACCORDIN6 TO errs
• 8 bits microcontroller : executes logic & arithmetic
op~rations. example: Intel 8031/8051.
• 16 bits microcontroller: executes with greater accuracy and
performance in contrast to 8-bit. example: Intel 8096.
• 32 bits microcontroller: is employed mainly in automatically
controlled appliances such as office machines, implantable
medical appliances, etc. It requires 32-bit instructions to carry
out any logical
or arithmetic function.
INSl'RUCfION SET
• CISC (complex instruction set computer): it allows the
user to apply 1 instruction as an alternative to many simple
instructions.
• RISC (Reduced Instruction Set Computers): RISC
reduces the operation time
by shortening the clock cycle per
instruction.
i