8051 Microcontroller

Intel’s

8051

Micro controller

Basics
What are Micro controller's ? Why the name Micro controller ?
Basically used for control actions.It is used to control the operation of machine using fixed program that is stored in ROM/EPROM and that does not change over the life time.

What is MCS 51 ?

Why to study 8051 ?
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Features of 8051
8 bit ALU. 16 bit PC and DPTR. 8 bit stack pointer and 8 bit PSW. 4K internal ROM 128 bytes of Internal RAM. 32 bits arranged as four,8 bit ports P0-P3. Two 16 bit timer/counters, T0 & T1. Full duplex serial Port.
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Features contd…
Control Registers TCON,TMOD,SCON,PCON,IP,IE etc (SFR’s). Two External and three internal interrupt sources. 0-12 MHz clock. 40 pin DIP package. Works in Power Down and Idle mode. Powerful Instruction set.
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Block Diagram of 8051.

Pin Diagram of 8051

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Internal RAM Organization

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Internal RAM Organization

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Clock for 8051.

Tin = N * 12 / Clk.Freq

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Program Status Word (PSW)
7
CY

6
AC

5
F0

4

3

2

1

0
P

RS1 RS0 OV ---

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I/O Ports of 8051-Port 0

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I/O Ports of 8051-Port 1

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I/O Ports of 8051-Port 2

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I/O Ports of 8051-Port 3

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Memory Interfacing with 8051
How to interface Program memory(EPROM) up to 64 KB to 8051 ? How to interface Data memory(RAM) upto 64 KB to 8051 ? How 8051 distinguishes Program and data memory operations ?

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Timer Control Register (TCON)
7
TF 1

6
TR1

5
TF0

4
TR0

3
IE 1

2
IT1

1
IE0

0