The microcontroller incorporates all the characteristics that are found in microprocessor. The microcontroller has built in ROM. RAM. Input Output ports. Consecutive Port. timers. interrupts and clock circuit. A microcontroller is an full computing machine manufactured on a individual bit. Microcontrollers are normally dedicated devices embedded within an application. For illustration. microcontrollers are used as engine accountants in cars and as exposure and focal point accountants in cameras. In order to function these applications. they have a high concentration of on-chip installations such as consecutive ports. parallel input end product ports. timers. counters. disrupt control. analog-to-digital convertors. random entree memory. read merely memory. etc.
The I/O. memory. and on-chip peripherals of a microcontroller are selected depending on the particulars of the mark application. Since microcontrollers are powerful digital processors. the grade of control and programmability they provide significantly enhances the effectivity of the application. The 8051 is the first microcontroller of the MCS-51 household introduced by Intel Corporation at the terminal of the seventiess. The 8051 household with its many enhanced members enjoys the largest market portion. estimated to be approximately 40 % . among the assorted microcontroller architectures.
The microcontroller has on bit peripheral devices. In this unit foremost we differentiate microcontroller from microprocessor so we will discourse about Hardware inside informations of 8051 and so present the Assembly degree linguistic communication in brief. Microcontrollers
• Microcontroller ( MC ) may be called computing machine on bit since it has basic characteristics of microprocessor with internal ROM. RAM. Parallel and consecutive ports within individual bit. Or we can state microprocessor with memory and ports is called as microcontroller. This is widely used in rinsing machines. vcd participant. micro-cook oven. robotics or in industries.
Microcontroller and Embedded Systems
• Microcontroller can be classified on the footing of their spots processed like 8bit MC. 16bit MC.
• 8 spot microcontroller. means it can read. compose and treat 8 spot informations. Ex. 8051 microcontroller. Basically 8 spot specifies the size of informations coach. 8 spot microcontroller means 8 spot informations can go on the informations coach or we can read. compose procedure 8 spot informations.
PIN DIAGRAM OF 8051 MICRO CONTROLLER:
Description of each pin is discussed here:
• VCC ??5V supply
• VSS: GND
• XTAL2/XTALI are for oscillator input
• Port 0 – 32 to 39 – AD0/AD7 and P0. 0 to P0. 7
• Port 1 – 1 to 8 – P1. 0 to P1. 7
• Port 2 – 21 to 28 – P2. 0 to P2. 7 and A 8 to A15
• Port 3 – 10 to 17 – P3. 0 to P3. 7
• P 3. 0 – RXD – Serial information input – SBUF
• P 3. 1 – TXD – Serial information end product – SBUF
• P 3. 2 – INT0 – External interrupt 0 – TCON 0. 1
• P 3. 3 – INT1 – External interrupt 1 – TCON 0. 3
• P 3. 4 – T0 – External timer 0 input – TMOD
• P 3. 5 – T1 – External timer 1 input – TMOD
• P 3. 6 –WR – External memory write rhythm – Active LOW
• P 3. 7 – RD – External memory read rhythm – Active LOW
• RST – for Restarting 8051
• ALE – Address latch enable
1 – Address on AD 0 to AD 7
0 – Data on AD 0 to AD 7
• PSEN – Program shop enable
Each block is explained as:
ALU — Arithmetic Logical Unit
This unit is used for the arithmetic computations.
This registry is used for arithmetic operations. This is besides bit addressable and 8 spot registry.
This registry is used in merely two instructions MUL AB and DIV AB. This is besides bit addressable and 8 spot registry.
• Points to the reference of following direction to be executed from ROM
8051 Flag Bits and PSW Register
1. Used to bespeak the Arithmetic status of ACC.
2. Flag registry in 8051 is called as plan position word ( PSW ) .
This particular map registry PSW is besides bit addressable and 8 spot broad means each spot can be set or reset independently.
There are four flags in 8051
• P > Parity flag > PSW 0. 0
1 – uneven figure of 1 in ACC
0 – even figure of 1 in ACC
• OV ( PSW 0. 2 ) > overflow flag > this is used to observe mistake in signed arithmetic operation. This is similar to transport flag but difference is merely that carry flag is used for unsigned operation.
AC > Auxiliary carry flag > when carry is generated from D3 to D4. it is set to 1. it is used in BCD arithmetic.
CY > carry flag > Affected after 8 spot add-on and minus. It is used to observe mistake in unsigned arithmetic opr. We can besides utilize it as individual spot storage.
SETB C ; for cy = 1
CLR C ; for cy = 0
Structure of RAM or 8051 Register Bank and Stack
1. 128 byte RAM is available in 8051
2. 128 byte = 27B
3. 128 byte seeable or user accessible RAM is available which is shown in figure. Excess 128B RAM which is non user accessible. 80H to FFH used for storage of SFR ( particular map registry )
Stack in 8051
> RAM locations from 08H to 1FH can be used as stack. Stack is used to hive away the informations temporarily.
Stack is last in first out ( LIFO )
> Stack arrow ( SP ) :
• 8bit registry
• It indicate current RAM reference available for stack or it points the top of stack.
• Initially by default at 07H because first location of stack is 08H.
• After each PUSH direction the SP is incremented by one piece in MC after PUSH direction SP is decremented.
• After each POP direction the SP is decremented.
Wall Follower utilizing 8051 is built utilizing TSOP based infrared sensor faculty. The Right faculty is used to observe the wall on the right of iBOT. Wall follower application can be built with merely one faculty. but we are utilizing the other detector to avoid obstruction in forepart of the automaton. The Right faculty is connected at about 45 grade to the board so as to observe the wall as shown in the image.
Here we are utilizing 2 IR TSOP faculties and iBOT will follow the wall on its right. The right TSOP faculty is for observing the wall and the left faculty is used to avoid the iBOT from knocking into the forepart wall or obstruction.
Here if BOT detects wall on right it goes off from the wall. if it does non observe wall on right it goes right until the wall is detected.
The TSOP Sensor with Robosoft Systems is a miniaturized receiving system for infrared distant control systems. PIN rectifying tube and preamplifier are assembled on lead frame. the epoxy bundle is designed as IR filter. The demodulated end product signal can straight be decoded by a microprocessor. TSOP is the standard IR remote control receiving system series. back uping all major transmittal codifications. Features:
1. Photo sensor and preamplifier in one bundle
2. Internal filter for PCM frequence
3. Improved screening against electrical field perturbation
4. TTL and CMOS compatibility
5. Output active low
6. Low power ingestion
7. High unsusceptibility against ambient visible radiation
8. Continuous informations transmittal possible ( up to 2400 bits per second )
1. Supply Voltage: –0. 3…6. 0 V.
2. Supply Current: 5 ma.
3. Output Voltage: –0. 3…6. 0 V.
4. Output Current: 5 ma.
5. Junction Temperature: 100 °C