MicrocontrollersLab 2

GENERATE PATTERNS ON LED USING 8051

Objectives of the LabInterfacing LEDs using 8051 ports as output ports.

Generating Delay using Delay Subroutine.

Checking Working of Code on Proteus.

Programming 8051 using Smart-PRO Burner.

Deciding Pins or Ports to use

Use withcaution

If EA high,P0 & P2 aresimple portsotherwiseaddress bits

*We can use any port, for now we will use P2.

Introduction to Assembly in 8051An assembly language instruction consists of four fields. [Label:] mnemonic [operands] [;comments]Label is used to jump to a specific code location from

any other location.Mnemonic is used for opcode of command e.g. add, mov.Operands are used to mention the registers or constants

used by command.Comment field is used to make the code user friendly.Square brackets show that these fields are optional.

ReviewRegisters (Naming) Normally UsedAccumulator (A or ACC) Base (B)Ports (P0,P1,P2,P3 & Px.y) PSW (For Flags & Register Banks)R0,R1,…,R7 SP(Stack Pointer)DPTR(Data Pointer) Timer RegistersSerial Port Registers Interrupt RegistersPCON (Power Control Register)

IP (Instruction Pointer)

Legend:* Frequently used* Special Functions* Occasionally* Used automatically

Instructions used in this LabMOV DEST,SOURCE

mov p0,#10101001b mov p0,#0A9hmov p0,#169d or mov p0,#169

JMP LABELDJNZ REG,LABELRL ARR ASee instruction set for the details of above commands.

Algorithm to generate LED patternsStart

Send seq to output

First Sequence

Next Sequence

Call Delay

*Controller Programs tend to run forever i.e. in the infinite loop.

mov a,#seq

mov p2,a

rr a

call delay

ReviewProgram Structure (Directives)org 00h...call delay...

delay: ;subroutine...retend

Delay subroutine:delay:

mov r6,#2

dl1:

mov r7,#10

dl2: djnz r7,dl2 ; djnz r7,$

djnz r6,dl1

ret

Delay Calculationdelay:

mov r6,#x

dl1:

mov r7,#y

djnz r7,$

djnz r6,dl1

ret

1

1

2 * y * x

2

2*Refer to instruction set for delays of individual commands

Delay= (2y+1+2)x+1+2 =(2y+3)x+3 machine cycles Putting in the values of x and y, we can calculate delay in machine cycles and then we can calculate the time by multiplying this by the time one machine cycle takes.

Generating Required Delay1. We discussed that the above subroutine creates delay of (2y+3)x+3 machine

cycles. To convert this delay into time, we need to replace machine cycle by

the time it takes.

2. For a 12 MHz crystal, 1mc = 1µs, and delay=(2y+3)x+3µs.

3. If we want to create delay of 100 milli-seconds, then 100ms=(2y+3)x+3µs,

one equation, two unknown, assume some value of ‘y’ and find out ‘x’.

4. If the above calculated values of ‘x’ and ‘y’ are used, one will be able to

generate delay of 100 ms, using a 12 MHz crystal.

*Calculate values of x and y for generating delay of 100 ms with XTAL=11.0592 MHz

Using Proteus to simulate 8051 codes1. The ‘HEX’ file generated by ‘keil’ or any other software as such can be

used to check the working of code on software using proteus.

2. Just search for ‘AT89c51’, place the controller, double click on it to edit

properties

1. Change the clock frequency to 11.0592 MHz.

2. Click the ‘folder icon’ in front of Program files and locate the code hex file.

3. In advanced properties, select ‘Simulate Program Fetches’ and ‘Yes’.

3. Then, place other devices, interconnect with 8051 and simply play the

simulation.

How to program a µC using SmartPro 2008 (Programmer)

1. Connect your SmartPro 2008 Programmer to PC via

USB port and turn the device on using its adapter. Also,

place the µC carefully in the ZIF socket.

2. Locate and click ‘SmartPro 2008’ icon available on

desktop.

3. If it asks for the Programmer Select ‘Smart PRO 5000u’

and click demo.*One must check, how to place different types of controller in the programmer.

How to program a µC using SmartPro 2008 (Programmer)4. Click ‘Select Device’ on the window or choose Device>Select or

press Ctrl+S.

1. In ‘Type’, select ‘MCU’

2. In ‘Manufacturer’, select ‘ATMEL’ , AT89Cxx.

3. In ‘Device’, select AT8951.

5. Now, select File>Open or press Ctrl+O, in ‘files of type’ select

Intel Hex and locate the ‘HEX’ file you want to program. Also,

see if buffer is loaded with the new ‘HEX’ file.

How to program a µC using SmartPro 2008 (Programmer)6. Now, there are a bunch of options that can be performed depending upon the

users needs.

1. F4 or Click ‘Read’: Reads a previous program already burned in the µC.

2. F5 or ‘Erase’: Erases the previous program in µC.

3. F6 or ‘Blank Check’: Verification if program is erased.

4. F7 or ‘Program’: Loads the *current HEX file in µC.

5. F8 or ‘Verify’: Verification if the program is properly loaded.

6. ‘Batch’: This option is used in Industry.

7. Spacebar or ‘Auto’: Performs all the steps from 2 to 5 in sequence.

7. Shortcut: Open SmartPro, slect device, locate hex file & press spacebar.

Debugging with µC1. Unlike electronic circuits, the debugging with µC is different. Firstly,

there is software debugging and then there is hardware debugging.

2. The software debugging includes the working of code.

3. The hardware debugging includes the working of code on hardware

and the devices interfaced.

4. Always perform µC experiment in three stages, test the µC IC and

generic board using led blinking, then verify the working of code on

Proteus software, then finally test the program on hardware.

Proteus Devices needed in this Lab1. AT89c51

2. LED Bargraph

3. Resistor Pack

Lab TasksBlink LED’s in different patterns with delay of

100 milli-seconds.Pattern 1: Blink LEDs towards right.Pattern 2: Blink LEDs towards left.Pattern 3: Blink even LEDs only.Pattern 4: Blink LEDs in the sequence

10000001,01000010,00100100,00011000.