1 / 62

Motorola MC68HC811E2 Microcontrollers

Motorola MC68HC811E2 Microcontrollers. What will be covered within 3 classes. Class 1 Friday March 14 th (home work due Tuesday) What are Microcontrollers/Microprocessors Intro into the HC11 chip Registers, accumulators, Condition Code register, memory map and other components

padma
Download Presentation

Motorola MC68HC811E2 Microcontrollers

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Motorola MC68HC811E2Microcontrollers

  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 MC68HC811E2Microcontroller

  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: 255+1 = 0 + carry high • V = Overflow ex: 255+1 = 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 • 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 MC68HC811E2Microcontrollers 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: #b101010 = #$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 0100 86 0101 55

  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 0100 36 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 0100 96 0101 55 … 0055 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 0100 A6 0101 55 … 1055 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 $2055 ‘load contents from address $2055 hex into accA Object code: Memory location Memory contents 0100 B6 0101 20 0110 55 … 2055 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 32 +1 positions Object code: Memory location Memory contents 0100 20 0101 20 0110 55 … 100100 RR 100101 DD Note: After branch, PC = 100110 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 #$FE ‘branch backwards 2 - 1 positions Object code: Memory location Memory contents 0010 YY 0011 XX 0100 20 ‘BRA #$FE 0101 FE 0110 55 … 100100 RR 100101 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 BSRSUB FD00 SUB NOP FD01NOP FD02 RTS Memory map 00FF02 00FEF8

More Related