Unit-6
Microprocessor
The microprocessor is an integrated circuit that comprises all the functions of the
central processing unit of a computer
A microprocessor is a CPU of a computer. It is a programmable integrated device
that has computing and decision making capability.
Evolution of microprocessor
The microprocessors are classified depending on the number of bits on which the
ALU can operate at a time.
First microprocessor was introduced by Intel in the year 1971. It was called
Intel 4004 and is a 4 bit PMOS processor comprising of 2300 transistors.
CLK speed of 180 KHz. 4 bit data bus width and 4 bit address bus width.
No. of instructions: 46. It was made by other companies also like Tosiba,
Rockwell,etc. These were called the First generation Microprocessor
In 1972 Intel launched an 8-bit microprocessor called 8008. It used PMOS
technology. It was very slow and was not compatible with TTL logic. It has
3500 transistors. Its clock speed is 500 KHz and 800 KHz. Its data bus width
is 8 bits and its address bus width is 8 bits. No. of instructions: 66. (it can
handle interrupts).
In 1974 Intel introduced a faster NMOS microprocessor Intel 8080. This was
the second generation microprocessor. It has 4500 transistors. CLK speed
of 2 MHz. 8 bit data bus width and 16 bit address bus width. No. of
instructions: 111. (needs three power supplies, +5V, -5V and +12V)
Motorola introduced in 1974 a new 8 bit processor MC 6800 that operates on
single +5V supply. It has 4000 transistors. CLK speed of 1 MHz. Its data bus
width is 8 bits and its address bus width is 16 bits. No. of instructions: 72
Unit-6 1
Unit-6
Microprocessor
The microprocessor is an integrated circuit that comprises all the functions of the
central processing unit of a computer
A microprocessor is a CPU of a computer. It is a programmable integrated device
that has computing and decision making capability.
Evolution of microprocessor
The microprocessors are classified depending on the number of bits on which the
ALU can operate at a time.
First microprocessor was introduced by Intel in the year 1971. It was called
Intel 4004 and is a 4 bit PMOS processor comprising of 2300 transistors.
CLK speed of 180 KHz. 4 bit data bus width and 4 bit address bus width.
No. of instructions: 46. It was made by other companies also like Tosiba,
Rockwell,etc. These were called the First generation Microprocessor
In 1972 Intel launched an 8-bit microprocessor called 8008. It used PMOS
technology. It was very slow and was not compatible with TTL logic. It has
3500 transistors. Its clock speed is 500 KHz and 800 KHz. Its data bus width
is 8 bits and its address bus width is 8 bits. No. of instructions: 66. (it can
handle interrupts).
In 1974 Intel introduced a faster NMOS microprocessor Intel 8080. This was
the second generation microprocessor. It has 4500 transistors. CLK speed
of 2 MHz. 8 bit data bus width and 16 bit address bus width. No. of
instructions: 111. (needs three power supplies, +5V, -5V and +12V)
Motorola introduced in 1974 a new 8 bit processor MC 6800 that operates on
single +5V supply. It has 4000 transistors. CLK speed of 1 MHz. Its data bus
width is 8 bits and its address bus width is 16 bits. No. of instructions: 72
Unit-6 1
