MCU – Microcontroller Unit – 1

MCU 1 cip or VLSI core – application-specific

• Embedded system: is a system whose principal function is not computational, but which is controlled by a computer embedded within it.

Examples: Refrigerator

Examples: Car Door

Examples: Derbot Autonomous Guided Vehicle

Examples: Derbot Autonomous Guided Vehicle

• The microprocessor is a processor on one silicon chip.

• The microcontrollers are used in embedded computing.

• The microcontroller is a microprocessor with added circuitry.

Microcontrollers

Microcontroller Packaging and Appearance

Some slides above are from - Dr. Gheith Abandah

From left to right: PIC 12F508, PIC 16F84A, PIC 16C72, Motorola 68HC05B16, PIC 16F877, Motorola 68000

Types of MCU

– 8/16/32-bit mcu – internal bus & instruction size, ALU

– Instruction sets – RISC/CISC • Complicated instruction set comp [CISC]

– It has an instruction set that supports many addressing modes. – It offers flexibility in choosing various ways of performing the data

transfer and ALU ops.

• Reduced ISC [RISC]– Supports 1/2 addressing modes– Need many registers – so need less fetching from external

memories for operations… so higher performance in computing than CISC… e.g., ARM

Types of MCU

– Memory architecture • Harvard mem has a distinct mem address space for i. Program mem & ii. Data mem It has separate instructions , hence separate control signal[s], for data transfers

from these two memories.

• Princeton mem has a common mem space for both. So no need for separate …

Types of MCU– Family

• 8051 – Intel – Philips– Atmel– Siemens– Dallas

• Motorola • PIC - Peripheral Interface Controller

• Hitachi• Texas • ARM - Advanced RISC Machine (previously known as Acorn RISC Machine)

• Others

Selection of MCU

• Checklist – 8/16/32 bit ALU– Max. power dissipation– Clock speed needed– Instructions set RISC/CISC

Selection of MCU…

• Checklist – – Memory architecture– Memory size– Cache, memory management unit, DSP

calculations– Internal PROM/…– I/O ports– Cost

Selection of MCU…

• Additional checklists – Cost when single chip and when MCU interfaces to

circuit with some features– Major building blocks of hardware cost and

availability – Major building blocks of software cost and

availability – Ease of integration – Design team expertise– Manpower

Applications

Numerous! e.g.,

• Biomedical instruments • Communication systems• Controller• Instrumentations• Control systems • Automotive apps, etc.

• Program mem – mainly Volatile / ROM• Data mem - non-volatile mem / RAM

Intel 8051/8031 architecture

• CPU has the control and sequencing logic circuits, ALU, Flags, clock

• Program mem - ROM• Interrupt control ckt• Internal timing devices – timer• Serial interface • Data mem - RAM

Intel 8051/8031…

• Special function registers• Ports • Register banks – 4 set of registers• RST – reset pin• INT – interrupt pins• VCC – voltage supply pin• GND