Why microcontrollers in embedded systems? One of the most critical needs of an embedded system is to decrease power consumption and space. In high-performance embedded processors, the trend is to integrate more functions on the CPU chip and let designer decide which features he/she wants to use. 19-Sep-18 Micro 8051

What criteria do designers consider in choosing microcontroller? Four major 8-bit microcontroller, Freescale’s 6811 Intel’s 8051 Zilog’s Z8 PIC 16Xx from microchip technology Each of these microcontrollers has a unique instruction and register set , therefore they are not compatible with each other. 19-Sep-18 Micro 8051

Continues… Program written for one will not run on the others with all the microcontroller, there are three criteria in choosing microcontroller are as follows, Meeting the computing needs of the task at hand efficiently and cost effectively. Speed Packaging Power consumption The amount of RAM and ROM on chip The number of I/O pins and the timer on chip 19-Sep-18 Micro 8051

Continues… How easy to upgrade to higher performance or lower power-consumption versions Cost per unit. Availability of software development tools such as assemblers, compilers, and debuggers. Wide availability and reliable sources of the microcontroller. 19-Sep-18 Micro 8051

TYPICAL APPLICATIONS OF MICROCONTROLLERS HOUSEHOLD ITEMS: Toys, camera, robot, video recorders, CD players, Microwave ovens,washing machine, vaccum cleaners, garage door opener, home security system,TV’s,Video Games. OFFICE EQUIPMENT'S: Fax machine, printers, plotter, modem, smart cards. 19-Sep-18 Micro 8051

Continues… COMMUNICATION EQUIPMENT'S: Cordless phone, Pagers,Answering machines, Telephone sets. INTELLIGENT INSTRUMENTS: Oscilloscope , Various Medical Instruments PROCESS CONTROL: Data acquisition and control in steel industries. 19-Sep-18 Micro 8051

Some more applications Automobile engine Flight control systems Traffic light control systems Military applications. Microcontrollers have an enormous influence in improving the quality of our day to day lives. 19-Sep-18 Micro 8051

DIFFERENT TYPES OF MICROCONTROLLER EMBEDDED MICROCONTROLLERS: When a complete hardware required to run a particular operation is provided on the microcontroller chip it is referred as an embedded microcontroller. It require power, reset circuit and clock. Embedded microcontrollers communicate with external device with its digital input and output pins. 19-Sep-18 Micro 8051

Continues…. EXTERNAL MEMORY MICROCONTROLLERS: For larger system, the built in program memory and data memory are insufficient. To overcome this problem some microcontrollers allow the connection of external memory some parallel port pins are used as address and data lines. These address and data lines are multiplexed and separate by external latch and ALE signal from the microcontroller. 19-Sep-18 Micro 8051

Address Multiplexing for External Memory (code) 19-Sep-18 Micro 8051