1. Motorola MC68HC811E2 Microcontrollers

2. 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

3. 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)

4. 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.

5. What they are used for Remote monitoring equipment
Car computer systems
Automating equipment
Cell phones
Computers
Palm Pilots
Singing gift cards

6. Motorola MC68HC811E2 Microcontroller

7. HC11 Power saving (stop) and (wait) modes 2048 bytes of EEPROM
256 bytes of RAM
16 bit timer
8-bit pulse accumulator
Real time interrupt circuit
Computer operating properly (COP) watchdog system

8. 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) converters
38 general purpose I/O pins
16 bidirectional
11 input only, 11 output only
Available in 52pin (PLCC) or 48 pin (DIP) packages

9. Internal Structure of the chip

10. Nomenclature and symboles
Vdd and or Vss mean +5 volts.
GND = ground or 0 volts
PA1 means Port A pin 1
Vrl = voltage reference low
Vrh = voltage reference high
Some 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”.

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

12. Oscillator All CPUs need an oscillator to jump between commands.
HC11 is a 4 cycle command chip
Operates at 2Mhz with an 8Mhz cristal

13. 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

14. 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)

15. Ports

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

17. 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

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

19. 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.

20. Chip Layout

21. CPU Registers HC11 has five registers and two accumulators
Accumulator D = accA + AccB to form a 16 bit accumulator

22. Condition Code Register (CCR)
C = Carry bit, ex: = 0 + carry high
V = Overflow ex: = 0 and v=1 as the sum has overflowed capacity
Z = zero bit ex: 1-1 = 0, z=1
N = negative ex: 4-6 = $FD z=1
I = interrupt mask, enables inturrupts
H = 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)

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

24. Stack pointer
Stack is usually initialized at the top of memory and works down
The program is located at the bottom of memory and works up
If the stack grows too big, it may overwrite the program, causing a fatal crash
HC11 has 256 bytes of RAM for the stack
16 bit register

25. Index Registers HC11 has two index registers X & Y are 16 bits wide
Used to index memory fetch or storage of large numbers

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

27. Memory Map

28. Memory Map 256 Bytes of RAM at top of memory address
2K EEPROM from $F800 to $FFFF
64 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

29. End of Day 1 Assignment Part1 Part2
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

30. Example of Block Diagrams

31. Example 2 of flow diagram

32. Motorola MC68HC811E2 Microcontrollers
Day 2

33. Topics that will be covered
Motorola Language Code
Data type and symbols
Opcodes, Operands and addressing modes

34. Data types The default numbering system is decimal in most compilers
Hexadecimal number are represented by a $ symbol. Ex: $FF = 255 decimal
A number is defined by a# ex1: #45 = 45 decimal. Ex2: #$45 = 69 decimal
Binary number are identified by a b. ex: #b = #$2A = #42 decimal
Octave numbers are identified by an o ex: #o10 = #$9 = #9 decimal

35. Instruction Set (hand out in class)
Mnemonic = command
Operation = what it does
Description = description of how it does it
Addressing mode = the way it does it
Opcode = machine code that the HC11 sees
Cycles = number of cycles needed to compute
CCR = affected condition code after execution

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

37. 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

38. Example of Immediate Source list: LDAA #$55 ‘load 55 hex into accA
Object code:
Memory location Memory contents

39. 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

40. Example of Inherent Source list: PSHA ‘push accA to stack Object code:
Memory location Memory contents
Note: SP = SP -1

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

42. Example of direct Source list:
LDAA $55 ‘load contents from address $0055 hex into accA
Object code:
Memory location Memory contents … XX
Note: After insturction, accA = XX

43. 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 address
The effective address is held in a temporary address register so that the contents of the index register are not changed

44. Example of Indexed Source list: ‘X=#$1000
LDAA #$55,X ‘load contents from address ($55 + X) hex into accA
Object code:
Memory location Memory contents A6 … YY
Note: After insturction, accA = YY

45. Extended Addressing mode
Used to address locations in full memory map
2nd memory location = address high byte
3rd memory location = address low byte

46. Example of Extended Source list:
LDAA $ ‘load contents from address $2055 hex into accA
Object code:
Memory location Memory contents B6 … ZZ
Note: After instruction, accA = ZZ

47. Relative Addressing Mode
Used for branch type instructions
Program control may be transferred to some place other than the next sequential memory location
Transfer is referenced from the next instruction which the MCU would execute if it did not transfer control
2 byte instruction
2nd byte contains the offset, which is the number of memory locations to branch over
Offset is expressed as an 8 bit 2’s compliment number

48. Example of Relative Branch forward example Source list:
BRA #$20 ‘branch forward positions
Object code:
Memory location Memory contents … RR DD
Note: After branch, PC = and executing DD opcode
Note2: Note that opcode for BRA = 20hex, and so is the jump. This is why a miscalculation of branching can crash your program

49. Example of Relative Branch Backwards example Source list:
BRA #$FE ‘branch backwards positions
Object code:
Memory location Memory contents YY XX
‘BRA #$FE FE … RR DD
Note: After branch, PC = 100 and executing 20 opcode
Note2: Infinit loop

50. 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 NOP
FD01 NOP
FD02 RTS
Memory map
00FF 02
00FE F8

51. Useful Opcodes ABA ADDA ANDA BCC BEQ BITA BRA BRSET CLC CLI CLR CLRA
CMPA
COM
DEC
DECA
DEX
INCA
INS
INX
JSR
LDAA
LSR
NEGA
RTI
RTS
SEC
SEI
STAA
STX
SUBA
SWI
TAB
WAI

52. Program example1 Example1: Determine: ORG $0000 LDX #$0060
LDAA $02
LDAB 2,X
ABA
ORG $0060
FCB $70,$72,$74,$76
END
S=1, X=0, I =0
Determine:
accA = _________
accB = _________
PC = ___________
CCR = __________binary
CCR = __________Hex

53. Program example1 accA = $60+ $74 = $D4 Example1: accB = $74 ORG $0000
PC = $0008
CCR = b
CCR = $88
Example1:
ORG $0000
LDX #$0060
LDAA $02
LDAB 2,X
ABA
ORG $0060
FCB $70,$72,$74,$76
END

54. Program example2 Example2: ORG $0F00 LDS #$10FF LDX #$0F00 LDAA 2,X
LDAB #01
PSHA
PSHB
BSR SUB1
NOP
ORG$0F50
PULA
PULB
ABA
RTS
END
S=1, X=0, I =0
Determine:
accA=
accB=
PC =
CCR =
SP =
IX =
Does the code work? Explain.

55. Program example2 Example2: ORG $F800 LDS #$00FF LDX #$F800 LDAA 2,X
LDAB #01
PSHA
PSHB
BSR SUB1
NOP
ORG$F850
PULA
PULB
ABA
RTS
END
S=1, X=0, I =0
Determine:
accA= $FF, $F8, $06
accB= $01, $0E
PC = $01FF
CCR = $A1
SP = $01FF
IX = $0F00
00FF FF
00FE 01
00FD 0E
00FC F8
The problem is that we return from the subroutine to a non-controlled position. Program will crash!

56. Program example3 Example3: ORG $F800 SEI LDX #$FA00 CLR 1,X CLR 3,X
LDAA #$FF
STAA 2,X
CLR 0,X
LDAA $02
STAA 1,X
STAA 3,X
LDAB #$FF
STAB 2,X
LDAA 0,X
ABA
END
S=1, X=0, I =0
Determine:
accA=
accB=
PC =
CCR =
IX =
Does the code work? Explain.

57. Program example3 Example3: ORG $F800 SEI LDX #$F8A0 CLR 1,X CLR 3,X
LDAA #$FF
STAA 2,X
CLR 0,X
LDAA $02
STAA 1,X
STAA 3,X
LDAB #$FF
STAB 2,X
LDAA 0,X
ABA
END
S=1, X=0, I =0
Determine:
accA= $FF, $00, $FF
accB= $FF
PC = $F81C
CCR = $88
IX = $F8A0
FA00 00
FA01 00, FA
FA02 FF, FF
FA03 00, FA
Does the code work? Explain.
Yes, the code is fully functioning

58. Example of Flow Diagram

59. Assignment Review Setup code for the Main Program for next Lab
Setup code for delay loop using nested loops

60. Your Flow Diagram Initialize Pause on? BSR Delay Input PortC Add Input
with accA
Output accA
To PortB

61. Delay Loop
Push A &B
Init A & B
DecA
A=0?
RTS
Pull A & B
DecB
B=0?

62. Assignement2 ORG $0000 SEI LDS #$0100 LDAA #03 CLRB BSR SUB ABA
SUB INCB
PSHB
DECA
BEQ CONT
CONT PULB
RTS
END
INITIALLY: S=1, X=0, I =0
CCR = SXHINZVC
Determine:
accA=
accB=
PC =
SP =
CCR =
What does this program do?