motorola mc68hc811e2 microcontrollers. what will be covered within 3 classes class 1 friday march 14...

Motorola MC68HC811E2Microcontrollers

What will be covered within 3 classes

Class 1 Friday March 14th (home work due Tuesday)

What are Microcontrollers/Microprocessors Intro into the HC11 chip Registers, accumulators, Condition Code register,

memory map and other components

Class 2 Monday March 17th Motorola Language Code Data type and symbols Opcodes, Operands and addressing modes

Class 3 (Tutorial) Tuesday March 18th Assembler programming Assembler Compiling Assembler Emulating All done using Oztech Electronics Software

Microprocessors

Microprocessors are components that compute binary mathematical commands at a specified rate determined by either an internal or external oscillating input. Characterized by:

Memory addresses registers Memory data registers Instruction registers Index registers Stack registers Accumulators Program counters Ex: Motorola Microprocessor 6800 (built in the 1980’s)

Microcontrollers

Microcontrollers are microprocessors that have built in peripherals, such as communications ports, I/O ports and others. These devices do not offer physical access to the address register and are usually standalone. They offer a fast and compact control method with limited physical connections and tools.

What they are used for

Remote monitoring equipmentCar computer systemsAutomating equipmentCell phonesComputersPalm PilotsSinging gift cards

Motorola MC68HC811E2Microcontroller

HC11

Power saving (stop) and (wait) modes2048 bytes of EEPROM 256 bytes of RAM16 bit timer8-bit pulse accumulatorReal time interrupt circuitComputer operating properly (COP) watchdog system

HC11

Synchronous Serial Peripheral Interface (SPI)Asynchronous Non return to Zero (NRZ) serial Communication Interface (SCI)8 channel, 8-bit analogue to digital (A/D) converters38 general purpose I/O pins 16 bidirectional 11 input only, 11 output only

Available in 52pin (PLCC) or 48 pin (DIP) packages

Internal Structure of the chip

Nomenclature and symboles

Vdd and or Vss mean +5 volts.GND = ground or 0 voltsPA1 means Port A pin 1Vrl = voltage reference lowVrh = voltage reference highSome pins have more than one function, these must be setup prior to use. Default is shown in manual.Pins with a line above mean “not” or anti” polar. Thus when 0volts or a “low” is shown at the reset pin, the chip interprets as a 1 or a “high”.

Reset pin

All chips have a master reset pin where a physical reset can occur. Used for emergencies Low power Frozen Testing Startup

OscillatorAll CPUs need an oscillator to jump between commands. HC11 is a 4 cycle command chipOperates at 2Mhz with an 8Mhz cristal

Interrupt Request Queue

There are many different interrupts on the HC11 Software IRQ (SIR) Multitude of input IRQ

Negative Edge Sensitive Positive Edge Sensitive

Non-maskable IRQ (XIRQ) Here nothing can stop the interrupt from

occurring. Always an external interrupt pin

Port A

Port A can be configured as: Four timer input capture (IC) Four timer output compare (OC) Combination of the two One pulse accumulator (PAI) General I/O (note directional limits)

Port B

Port B can be configured for: General purpose output pins Simple Strobed output Often used for 8-bit data

communication

Port C

Port C pins can be configured for: General I/O Used for full handshake modes during

parallel I/O Often used as multiplexed

address/data signal communication

Port D

Port D pins can be configured for: General I/O Serial Communication Interface (SCI) Serial Peripheral Interface (SPI)

Port E

Port E pins can be configured for: General purpose I/O Analogue for digital input (A/D) Note: for high accuracy of A/D, do not

read port E during sampling of A/D, as small disturbances can reduce the accuracy of the results.

Chip Layout

CPU Registers

HC11 has five registers and two accumulatorsAccumulator D = accA + AccB to form a 16 bit accumulator

Condition Code Register (CCR)

C = Carry bit, ex: 255+1 = 0 + carry highV = Overflow ex: 255+1 = 0 and v=1 as the sum has overflowed capacityZ = zero bit ex: 1-1 = 0, z=1N = negative ex: 4-6 = $FD z=1I = interrupt mask, enables inturruptsH = half carry (when carry is done from bit 3)X = X interrupt mask XIRQ (set only by hardware (XIRQ and Reset pins), cleared only by software)S = Stop disable (sleep mode mask)

Program Counter

The program counter always points to the next instruction location to be executed. 16 bit register

Stack pointer

Stack is usually initialized at the top of memory and works downThe program is located at the bottom of memory and works upIf the stack grows too big, it may overwrite the program, causing a fatal crashHC11 has 256 bytes of RAM for the stack16 bit register

Index Registers

HC11 has two index registersX & Y are 16 bits wideUsed to index memory fetch or storage of large numbers

Accumulators

Accumulator A is 8 bits longAccumulator B is 8 bits longAccumulator D = A + B, where B is the low byte and A is the high byte. AccD is used for large number handlingAccA and AccB are the main handlers of numbers within a program

Memory Map

Memory Map

256 Bytes of RAM at top of memory address2K EEPROM from $F800 to $FFFF64 byte register block is mapped initially starting from $1000 (this includes mapped address for ports, pins and internal configuration setup)All these can be remapped if needed

End of Day 1

Assignment Part1

Given a input on the lower nibble (4 bit) of PortC, increment a counter by the input value.

Display counter output on PortB (8 bit) Give a block diagram of events, decision and I/O

Part2 Give a block diagram of a delay loop Code the delay loop Q: Calculate the time it takes to cycle through

your delay loop. Hint: use a nested loop

Example of Block Diagrams

Example 2 of flow diagram

Motorola MC68HC811E2Microcontrollers

Day 2

Topics that will be covered

Motorola Language CodeData type and symbolsOpcodes, Operands and addressing modes

Data types

The default numbering system is decimal in most compilersHexadecimal number are represented by a $ symbol. Ex: $FF = 255 decimalA number is defined by a# ex1: #45 = 45 decimal. Ex2: #$45 = 69 decimalBinary number are identified by a b. ex: #b101010 = #$2A = #42 decimalOctave numbers are identified by an o ex: #o10 = #$9 = #9 decimal

Instruction Set (hand out in class)

Mnemonic = commandOperation = what it doesDescription = description of how it does itAddressing mode = the way it does itOpcode = machine code that the HC11 seesCycles = number of cycles needed to computeCCR = affected condition code after execution

Addressing modes

There are many ways of executing commands. There are six different addressing modes Immediate Direct Extended Indexed Inherent relative

Immediate

Argument is contained in the byte(s) immediately following the opcode.Number of bytes following the opcode matches the size of the register or memory location being operated on.The effective address is the address of the byte following the instruction

Example of Immediate

Source list:LDAA #$55 ‘load 55 hex into accA

Object code:Memory location Memory contents0100 860101 55

Inherent (accumulator/memory)

All information necessary to execute the instruction is contained in the opcode. Operations that use only the index register or accumulators, as well as control instructions with no arguments, are included in this addressing mode. These are one-byte or two-byte instructions

Example of Inherent

Source list:PSHA ‘push accA to stack

Object code:Memory location Memory contents0100 36

Note: SP = SP -1

Direct addressing mode

The address is found in the next memory location following the opcodeThis enables addressing the first page of memory (256 bytes)Execution time is reduced due to less consumption of space and movement of bits

Example of directSource list:

LDAA $55 ‘load contents from address $0055 hex into accA

Object code:Memory location Memory contents0100 960101 55…0055 XX

Note: After insturction, accA = XX

Indexed Addressing Mode

The offset, found in the second memory location of the instruction, is added to the contents of the index register to form a new effective addressThe effective address is held in a temporary address register so that the contents of the index register are not changed

Example of IndexedSource list: ‘X=#$1000

LDAA #$55,X ‘load contents from address ($55 + X) hex into accA

Object code:Memory location Memory contents0100 A60101 55…1055 YY

Note: After insturction, accA = YY

Extended Addressing mode

Used to address locations in full memory map2nd memory location = address high byte3rd memory location = address low byte

Example of Extended

Source list: LDAA $2055 ‘load contents from address

$2055 hex into accA

Object code:Memory location Memory contents0100 B60101 200110 55…2055 ZZ

Note: After instruction, accA = ZZ

Relative Addressing ModeUsed for branch type instructionsProgram control may be transferred to some place other than the next sequential memory locationTransfer is referenced from the next instruction which the MCU would execute if it did not transfer control2 byte instruction2nd byte contains the offset, which is the number of memory locations to branch overOffset is expressed as an 8 bit 2’s compliment number

Example of RelativeBranch forward example

Source list: BRA #$20 ‘branch forward 32 +1 positions

Object code:Memory location Memory contents0100 200101 200110 55…100100 RR100101 DD

Note: After branch, PC = 100110 and executing DD opcodeNote2: Note that opcode for BRA = 20hex, and so is the

jump. This is why a miscalculation of branching can crash your program

Example of RelativeBranch Backwards example

Source list: BRA #$FE ‘branch backwards 2 - 1 positions

Object code:Memory location Memory contents0010 YY0011 XX0100 20 ‘BRA #$FE0101 FE0110 55…100100 RR100101 DD

Note: After branch, PC = 100 and executing 20 opcodeNote2: Infinit loop

Subroutines

Branch to subroutine will push the PC onto the stack This allows the program to return to the program once the subroutine has been executed.

F800 BSR SUB

FD00 SUB NOPFD01 NOPFD02 RTS

Memory map00FF 0200FE F8

Useful OpcodesABAADDAANDABCCBEQBITABRABRSET

CLCCLICLRCLRACMPACOMDECDECA

DEXINCAINSINXJSRLDAALSRNEGA

RTIRTSSECSEISTAASTXSUBASWI

TABWAI

Program example1

Example1:ORG $0000LDX #$0060LDAA $02LDAB 2,XABA

ORG $0060FCB

$70,$72,$74,$76END

S=1, X=0, I =0

Determine:

accA = _________accB = _________PC = ___________CCR = __________binaryCCR = __________Hex

Program example1

accA = $60+ $74 = $D4accB = $74PC = $0008CCR = 1000 1000bCCR = $88

Example1:ORG $0000LDX #$0060LDAA $02LDAB 2,XABA

ORG $0060FCB

$70,$72,$74,$76END

Program example2Example2:

ORG $0F00LDS

#$10FFLDX

#$0F00LDAA 2,XLDAB #01PSHAPSHBBSR SUB1NOP

ORG$0F50PULAPULBABARTSEND

S=1, X=0, I =0 Determine:

accA=accB= PC = CCR = SP = IX =

Does the code work? Explain.


ORG $F800LDS

#$00FFLDX

#$F800LDAA 2,XLDAB #01PSHAPSHBBSR SUB1NOP

ORG$F850PULAPULBABARTSEND


accA= $FF, $F8, $06accB= $01, $0EPC = $01FFCCR = $A1SP = $01FFIX = $0F00

00FF FF00FE 0100FD 0E00FC F8

The problem is that we return from the subroutine to a non-controlled position. Program will crash!


ORG $F800SEILDX #$FA00CLR 1,XCLR 3,XLDAA #$FFSTAA 2,XCLR 0,XLDAA $02STAA 1,XSTAA 3,XLDAB #$FFSTAB 2,XLDAA 0,XABAEND

S=1, X=0, I =0Determine:

accA=accB= PC = CCR = IX =



ORG $F800SEILDX #$F8A0CLR 1,XCLR 3,XLDAA #$FFSTAA 2,XCLR 0,XLDAA $02STAA 1,XSTAA 3,XLDAB #$FFSTAB 2,XLDAA 0,XABAEND


accA= $FF, $00, $FFaccB= $FFPC = $F81CCCR = $88IX = $F8A0

FA00 00FA01 00, FAFA02 FF, FFFA03 00, FA


Yes, the code is fully functioning

Example of Flow Diagram

Assignment Review

Setup code for the Main Program for next LabSetup code for delay loop using nested loops

Your Flow DiagramInitialize

Pauseon?

Input PortC

Add Inputwith accA

Output accATo PortB

BSR Delay

Delay Loop Push A &B

Init A & B

DecA

A=0?Pull A & B

B=0?

DecBRTS

Assignement2ORG $0000SEILDS

#$0100LDAA #03CLRBBSR SUBABA

ORG $0080SUB INCB

PSHBDECABEQ CONTBSR SUB

CONT PULBABARTSEND

INITIALLY: S=1, X=0, I =0CCR = SXHINZVCDetermine:

accA=accB= PC = SP = CCR =

What does this program do?

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