DIGITAL DICE

USING

8051MICROCONTROLLERS

….. Man’s glory lies in his knowledge,

his upright conduct, his praise-worthy character,

his wisdom, and not in his nationality or rank

--Baha’ullah

(From, the book The 8051 Microcontroller and Embedded systems- Mazidi )

An EMBEDDED SYSTEM

• Means a processor is embedded in that application

• Only one application software typically burnt into the ROM

• Only one task can be performed using the micro controller/processor

• E.g. Video game player, printer, keyboard etc.

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Features of Different processor Architectures…

CISC

•Addressing modes.

•Variable length inst.

•No. of clocks >1

•Less general purpose internal registers

•x86,8051…

RISC

•Load/store Architecture generally.

•Fixed length instruction

•Generally inst.=1 clock

•More general purpose internal registers

•PIC,ARM,AVR…

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Address space architecture• Memory is needed for programs and data.• Program memory used in embedded systems is typically of

non-volatile type.• Data memory used is SRAM- or DRAM- type volatile

memory.

Von Neumann-architecture: Program and data located in same address space.

Harvard-architecture: Separate address spaces and buses for program and data memories.

Harvard Vs Von Neumann…

Need to learn Microprocessors/controllers

• The microprocessor is the core of computer systems.• Nowadays many communication, digital entertainment,

portable devices, are controlled by them.

• A designer should know what types of components he needs, ways to reduce production costs and product reliable.

• Reduce chip count.

• Many applications do not require as much computing power.

• Reduced power consumption.

• Reduced design cost

Necessary tools for a microprocessor/controller

• CPU: Central Processing Unit• I/O: Input /Output• Bus: Address bus & Data bus• Memory: RAM & ROM• Timer• Interrupt• Serial Port• Parallel Port

Microprocessor vs. Microcontroller

Microprocessor • CPU is stand-alone,

RAM, ROM, I/O, timer are separate

• designer can decide on the amount of ROM, RAM and I/O ports.

• expansive• versatility • general-purpose

Microcontroller• CPU, RAM, ROM, I/O

and timer are all on a single chip

• fix amount of on-chip ROM, RAM, I/O ports

• for applications in which cost, power and space are critical

• single-purpose

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•Useful for small computing tasks

•Adequate for many control and monitoring applications

•Used in communications as serial ASCII data is also stored in byte size.

•Most integrated circuit memories arranged in an 8-bit configuration

Eight - Bit Microcontrollers

Block Diagram Of 8051

CPU

On-chip RAM

On-chip ROM for program code

4 I/O Ports

Timer 0

Serial PortOSC

Interrupt Control

External interrupts

Timer 1

Timer/Counter

Bus Control

TxD RxDP0 P1 P2 P3

Address/Data

Counter Inputs

Pin Description of the 8051

1234567891011121314151617181920

4039383736353433323130292827262524232221

P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7RST

(RXD)P3.0(TXD)P3.1

(T0)P3.4(T1)P3.5

XTAL2XTAL1

GND

(INT0)P3.2(INT1)P3.3

(RD)P3.7(WR)P3.6

VccP0.0(AD0)P0.1(AD1)P0.2(AD2)P0.3(AD3)P0.4(AD4)P0.5(AD5)P0.6(AD6)P0.7(AD7)EA/VPPALE/PROGPSENP2.7(A15)P2.6(A14)P2.5(A13)P2.4(A12)P2.3(A11)P2.2(A10)P2.1(A9)P2.0(A8)

8051

Types of Microcontrollers

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Logic Symbols…

RESET Value of Some 8051 Registers:

0000DPTR

0007SP

0000PSW

0000B

0000ACC

0000PC

Reset ValueRegister

RAM are all zero.

Stack in the 8051

• The register used to access the stack is called SP (stack pointer) register.

• The stack pointer in the 8051 is only 8 bits wide, which means that it can take value 00 to FFH. When 8051 powered up, the SP register contains value 07.

7FH

30H

2FH

20H

1FH

17H10H

0FH

07H

08H

18H

00HRegister Bank 0

)Stack (Register Bank 1

Register Bank 2

Register Bank 3

Bit-Addressable RAM

General User RAM & Stack space

Internal RAM

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Alternate uses of Port- 3 pinsPINS ALTERNATE USE SFR

P3.0 RXD Serial data input SBUF

P3.1 TXD Serial data output SBUF

P3.2 INT0 External Interrupt 0 TCON.1

P3.3 INT1 External Interrupt 1 TCON.3

P3.4 T0 External Timer 0 I/P TMOD

P3.5 T1 External Timer 1 I/P TMOD

P3.6 WR External Memory write pulse -

P3.7 RD External Memory read pulse -

TMOD Register:

• Gate : When set, timer only runs while INT(0,1) is high.

• C/T : Counter/Timer select bit.

• M1 : Mode bit 1.• M0 : Mode bit 0.

TCON Register:

• TF1: Timer 1 overflow flag.• TR1: Timer 1 run control bit.• TF0: Timer 0 overflag.• TR0: Timer 0 run control bit.• IE1: External interrupt 1 edge flag.• IT1: External interrupt 1 type flag.• IE0: External interrupt 0 edge flag.• IT0: External interrupt 0 type flag.

Interrupts

Interrupt Enable Register :

• EA : Global enable/disable.• --- : Undefined.

• ET2 :Enable Timer 2 interrupt.• ES :Enable Serial port interrupt.• ET1 :Enable Timer 1 interrupt.• EX1 :Enable External 1 interrupt.• ET0 : Enable Timer 0 interrupt. • EX0 : Enable External 0 interrupt.

PROGRAM STATUS WORD

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Symbol Function

CY Used in arithmetic, jump, rotate & Boolean inst

AC Used for BCD arithmetic

F0 User flag 0

RS1 RS1 and RS0 used to select one of the 4

RS0 register banks of internal RAM

OV Used in arithmetic instructions

P Shows the parity of register A

CY AC F0 RS1 RS2 OV - P

Seven segment Interfacing

COMMANDS TO 7-SEGMENT

INSTRUCTION REGISTER

• CODE(HEX) COMMAND TO LCD INSTRUCTION REGISTER• 1 CLEAR DISPLAY SCREEN • 2 RETURN HOME • 4 DECREMENT CURSOR(SHIFT CURSOR TO LEFT) • 6 INCREMENT CURSOR(SHIFT CURSOR TO RIGHT) • 5 SHIFT DISPLAY RIGHT • 7 SHIFT DISPLAY LEFT • 8 DISPLAY OFF,CURSOR OFF • A DISPLAY OFF,CURSOR ON • C DISPLAY ON,CURSOR OFF • E DISPLAY ON CURSOR BLINKING • F DISPLAY ON CURSOR BLINKING • 10 SHIFT CURSOR POSITION TO LEFT • 14 SHIFT CURSOR POSITION TO RIGHT • 18 SHIFT THE ENTIRE DISPLAY TO THE LEFT • 1C SHIFT THE ENTIRE DISPLAY TO THE RIGHT • 80 FORCE CURSOR TO BEGINNING OF 1ST LINE • C0 FORCE CURSOR TO BEGINNING OF 2ND LINE • 8 2 LINES AND 5x7 MATRIX

LCD PIN DESCRIPTION

Pin No. Name Description Pin no. 1 D7 Data bus line 7 (MSB) Pin no. 2 D6 Data bus line 6 Pin no. 3 D5 Data bus line 5 Pin no. 4 D4 Data bus line 4 Pin no. 5 D3 Data bus line 3 Pin no. 6 D2 Data bus line 2 Pin no. 7 D1 Data bus line 1 Pin no. 8 D0 Data bus line 0 (LSB) Pin no. 9 EN1 Enable signal for row 0 and 1 (1stcontroller) Pin no. 10 R/W 0 = Write to LCD module 1 = Read from LCD module Pin no. 11 RS 0 = Instruction input 1 = Data input

Tie VEE (3) pin to 0V for maximum Contrast

THE FOLLOWING PROGRAM FEATURES:

» A DISPLAY » A TOGGLING LED &» A DICING 7-SEGMENT

org 00hacall LCDacall LEDacall DICELCD:mov a,#38hlcall commandmov a,#0fhlcall commandMov a,#01hLcall commandMov a,#80hLcall commandMov a,#’W’Lcall displayMov a,#’E’Lcall displayMov a,#’L’Lcall displayMov a,#’C’Lcall display1

Mov a,#’O’Lcall displayMov a,#’M’Lcall displayMov a,#’E’Lcall displayretCommand: lcall readyMov p1,aClr p3.2Clr p3.3Setb p3.4Clr p3.4RetReady: clr p3.4Clr p3.2Mov p1,#0ffhL1:setb p3.3Jb p1.7,L1Clr p3.4Ret

Display: lcall readyMov p1,aSetb p3.2Clr p3.3 Setb p3.4Clr p3.4RetDelay: mov r3,#25hHere: mov r1,#49hNopNopHere1:Djnz r1,here1Djnz r3,hereRetLED: mov p1, #00hLoop1: setb p1.2Acall delayClr p1.2Sjmp loop1retDICE: mov p1,#03fh

Acall delayMov p1,#06hAcall delayMov p1,#5bhAcall delayMov p1,#4fhAcall delayMov p1,#66hAcall delayMov p1,#6dhAcall delayMov p1,#7dhAcall delayMov p1,#07hAcall delayMov p1,#7chAcall delayMov p1,#67hAcall delayretend

CL

ICK

CL

ICK

SN

AP

THANKYOU!