MCU – Microcontroller Unit – 2 Md. Atiqur Rahman Ahad

Mechatronics ~ area of mechanical and electrical engineering – having integration of mechanics with electronics & information processing. The integration – between hardware & software  results an integrated system called mechatronic system. Microcontroller plays a major role in mechatronics

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

Internal structure of a MC

At times, a microcontroller can have external memory also (if there is no internal memory or extra memory interface is required). Most modern microcontrollers are manufactured with CMOS technology, which leads to reduction in size and power loss.

Harvard vs. Princeton Architecture In the late 1940's, the US Government asked Harvard and Princeton universities to come up with a computer architecture to be used in defense apps. Princeton suggested computer architecture with a single memory interface. Princeton architecture was accepted for simplicity and ease of implementation

Harvard suggested a computer with two different memory interfaces, one for the data / variables and the other for program / instructions. Harvard architecture became popular later, due to the parallelism of instruction execution.

Von Neumann architecture? Von Neumann architecture  after the name of the chief scientist of the project in Princeton University John Von Neumann (1903 - 1957 Born in Budapest, Hungary). How to remember? PN [junction!]  Princeton Neumann

Princeton /single mem interface

Harvard architecture

8051 microcontroller

8051 8051 employs Harvard [2] architecture. 8-bit CPU. 16-bit Program Counter 8-bit Processor Status Word (PSW) 8-bit Stack Pointer Internal RAM of 128bytes

8051… Special Function Registers (SFRs) of 128 bytes 32 I/O pins arranged as four 8-bit ports (P0 - P3) Two 16-bit timer/counters : T0 and T1 Two external and three internal vectored interrupts One full duplex [i.e., it can transmit and receive simultaneously] serial I/O has about 111 instructions

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

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 See – http://www.sonoma.eduusersffarahmansonomacourseses310es310_s10.htm

Intel 8051/8031… Special function registers Ports Register banks – 4 set of registers RST – reset pin INT – interrupt pins VCC – voltage supply pin GND Courtesy – http://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-KANPUR/microcontrollers/micro/ui/Course_home5_37.htm ‘PIC Microcontroller and Embedded Systems, by MA Mazidi et al., Pearson, 2012