Lecture Outline for Spring 2001

1. Wednesday 1/17

   • Introduction to Microprocessors and Microcontrollers.
   • Figures
     • Course Overview
     • Simple Cruise Control
     • Cruise Control Block Diagram
     • Cruise control flow chart
     • A microprocessor is just a state machine
     • Simple microcontroller -- a microprocessor with peripherals on a single chip
     • Harvard architecture microprocessor
     • Princeton architecture microprocessor
     • Microprocessor memory map

2. Friday 1/19

   • The HC12 Internal Registers (MC68HC912B Family , Sections 3.2-3.5;
   • CPU 12 Reference Manual, Sections 2.1-2.2)
   • Notes
     • 68HC12 Address Space
     • 68HC12 ALU
     • 68HC12 Programming Model
     • Some HC12 Instructions Needed for Lab 1
     • A Simple Assembly Language Program
     • Assembling an Assembly Language Program

3. Monday 1/22

   • Binary and hexadecimal numbers (Brown and Vranesic, Chapter 5).
   • Figures
     • Hex numbers can have a variety of meanings depending on the context
     • Binary, hex and decimal numbers
     • Converting unsigned binary numbers to decimal numbers
     • Converting unsigned hex numbers to decimal numbers
     • Converting decimal numbers to unsigned hex numbers - division
     • Converting decimal numbers to unsigned hex numbers - table
     • Hex representation of signed numbers -- two's complement form
     • How to take the two's complement of a number -- the one's complement table
     • Number wheel for 3-bit signed and unsigned numbers
     • Important things to remember when adding and subtracting hex and binary numbers
     • When are carries and overflows generated on addition?
     • How to tell if an addition or subtraction generates an overflow

4. Wednesday 1/24

   • Addition and Subtraction of Hex Numbers
   • Figures
     • Addition of Hex Numbers
     • Subtraction of Hex Numbers
   • Simple HC12 Programs
   • Figures
     • Execution of a simple program
     • A simple program
     • A simple program using assembler directives
   • Addressing Modes (CPU 12 Reference Manual, Section 3)
   • Figures
     • Things you need to know for assembly language programming
     • HC12 Addressing Modes
     • Inherent (INH) Mode

5. Friday 1/26

   • N, Z, V, C bits of Condition Code Register
   • Figures
     • How N, Z, V, and C bits of CCR are set and cleared
   • More on Addressing Modes (CPU 12 Reference Manual, Section 3)
   • Figures
     • Extended (EXT) Mode
     • Direct (DIR) Mode
     • Immediate (IMM) Mode
     • Indexed (IDX) Mode
     • Different Indexed Modes
     • Changing the flow of an HC12 program
     • Relative (REL) Mode
     • HC12 Addressing Modes

6. Monday 1/29

   • Assembly language programming on the 68HC12
   • Figures
     • Using assembler directives dc and ds
     • Assembler output of a simple program using dc and ds directives
     • Using the X and Y registers as address pointers
     • Cycle-by-cycle execution of a 68HC12 instruction
     • Counting the number of cycles to execute a program
     • Which branch instruction to use for signed and unsigned numbers

7. Wednesday 1/31

   • More on assembly language programming on the 68HC12
   • Figures
     • Symbols used for flow charts
     • If-Then flow chart structure
     • If-Then-Else flow chart structure
     • While flow chart structure
     • Do-While flow chart structure
     • Spaghetti structure - DO NOT USE
     • Flow chart to divide a table by two, and store in another location -- first attempt
     • Flow chart with code to divide a table by two, and store in another location -- first attempt
     • Flow chart to divide a table by two, and store in another location -- final attempt
     • Flow chart with code to divide a table by two, and store in another location -- final attempt
     • Assembly language program to divide a table by two, and store in another location
   • More on Assembly language programming on the 68HC12
   • 68HC12 Instructions (CPU 12 Reference Manual, Section 5)
   • Figures
     • Things to know for writing assembly language programs
     • Instructions used for copying data: Load/Store, Transfer/Exchange, and Move
     • Instructions used for arithmetic: Add/Subtract, Multiply/Divide, Increment/Decrement, Logical Operations, Compare and Test
     • Instructions used for changing program flow: Jump/Branch, Bit Test and Branch, Loop, Subroutines
     • Instructions to manipulate index registers and the condition code register
     • Miscellaneous instructions, some of which will be covered later in class

8. Friday 2/2

   • Writing a simple 68HC12 assembly language program
   • Figures
     • Definition of problem
     • Top-down design -- look at the big picture
     • Initialize pointers and variables
     • Process entries in table
     • Convert flow chart to instructions: How to determine if a number is odd, and how to tell when program reaches end of table
     • Final flow chart, with instructions for each block
     • Program to sum odd entries in a table
     • Program to swap entries in a table -- first start
     • swap entries in a table using a counter
     • swap entries in a table checking address pointers

9. Monday 2/5

   • Decoding HC12 instructions (CPU 12 Reference Manual, Appendix A)
   • Figures
     • Some op codes to disassemble
     • Determining what action a byte of a program will do (Table A-2)
     • Determining what action a loop instruction will do (Table A-6)
     • A disassembled program
   • More on 68HC12 assembly language programming -- use of the stack, stack pointer, and subroutines
   • Figures
     • The stack is a section of memory set aside for temporary storage. The stack pointer points to the last used byte of memory.
     • Use Push and Pull instructions to put things on the stack and take them off
     • Example of using the stack with a subroutine -- the return address is automatically placed on the stack
     • General information on the use of the stack in the 68HC12

10. Wednesday 2/7

    • More on Assembly language programming on the 68HC12 -- using a subroutine
    • 68HC12 Instructions (CPU 12 Reference Manual, Section 5)
    • Figures
      • Some tips for assembly language programming
      • A simple program using a subroutine
    • Communicating with the outside on the 68HC12 -- Introduction to Ports A and B in single-chip mode
    • M68HC12 Family Manual, Sections 6.2, 6.4
    • Figures
      • Concept of an input port
      • Concept of an output port
      • How to use PORTA on the 68HC12
      • DIP switches on a breadboard
      • Connecting DIP switches to an input port
      • Program to read data from input Port B, write to output Port A
      • A program fragment to read DIP switches connected to the 68HC12, and use that information to control program flow

11. Friday 2/9

    • More on Assembly language programming on the 68HC12
    • Figures
      • Pattern for LEDs
      • Flowchart for a program to make LEDs flash in a partiuclar pattern
      • A program to make LEDs flash in a partiuclar pattern
      • Using DIP switches with pull-up resistors connected to the 68HC12
      • A program fragment to read DIP switches connected to the 68HC12
    • Introduction to C programming on the 68HC12
    • Figures
      • Simple programs in both assembly and C
      • Programming constructs in both assembly and C
      • A simple C program, and instructions for compiling

12. Monday 2/12

    • More on C programming on the 68HC12
    • Figures
      • Use of pointers in C
      • Flow chart for counting negative numbers in memory
      • Flow chart with C code for counting negative numbers in memory
      • C program for counting negative numbers in memory
      • C include file which define all the registers in the HC12
      • C program to flash LEDs in a particular pattern
      • How to determine how long to loop to wait for 1 ms
      • C Programming Basics
      • Setting and clearing bits in assembly and C

13. Wednesday 2/14

    • Introduction to the free-running timer on the 68HC12
    • M68HC12 Family Manual, Sections 12.4.6, 12.4.8
    • Figures
      • The 68HC12 has a 16-bit timer running at 8 MHz
      • Checking to see if the timer has overflowed - wrong way
      • Checking to see if the timer has overflowed - right way, using the latched TOF bit
      • The 68HC12 16-bit timer - How to change the overflow rate
      • Testing bits and waiting for bits to change in Assembly and C
      • C and assembly programs to increment Port A and wait using the timer

14. Friday 2/16

    • What happens when you reset the 68HC12
    • M68HC12 Family Manual, Sections 4.7, 4.8
    • Figures
      • Reseting the 68HC12
    • Introduction to Interrupts: The HC12 Timer Overflow Interrrupt
    • M68HC12 Family Manual, Sections 4.4, 4.9
    • M68HC12 Family Manual, Sections 12.4.8, 12.4.9
    • Figures
      • Introduction to Interrupts
      • Generating timer overflow interrupts
      • Using interrupts on the HC12
      • Interrupt vectors, registers and stack before receiving a timer overflow interrupt
      • Interrupt vectors, registers and stack after receiving a timer overflow interrupt

15. Monday 2/19

    • More on the HC12 Timer Overflow Interrrupt
    • M68HC12 Family Manual, Sections 4.4, 4.9
    • M68HC12 Family Manual, Sections 12.4.8, 12.4.9
    • Figures
      • Interrupt vectors, registers and stack before receiving a timer overflow interrupt
      • Interrupt vectors, registers and stack after receiving a timer overflow interrupt
      • Assembly and C programs using timer overflow interrupts
      • Interrupt vectors, registers and stack before executing the rti instruction at the end of an interrupt service routine
      • Interrupt vectors, registers and stack after executing the rti instruction at the end of an interrupt service routine
      • Programming considerations when using timer interrupts

16. Wednesday 2/21

    • Review for Exam 1
    • Figures
      • Review for Exam 1

17. Friday 2/23

    • Exam 1

18. Monday 2/26

    • Interrupts: The HC12 Timer Overflow Interrupt and Real Time Interrupt
    • M68HC12B Family Manual, Section 10
    • Figures
      • What happens when the HC12 gets an unmasked interrupt
      • Generating a periodic interrupt using the Timer Overflow Interrupt
      • The Real Time Interrupt hardware
      • Generating a periodic interrupt using the Real Time Interrupt
      • The Timer Overflow and Real Time Interrupt hardware
      • Using the Timer Overflow and Real Time Interrupts in the same program
      • Interrupt rates for TOI and RTI
    • Introduction to the HC12 Input Capture Subsystem
    • M68HC12 Family Manual, Section 12
      • Using Port B and the TCNT register to measure the time between two events. Not very accurate
      • Can get accuracy by latching TCNT into a register when event happens
      • Input capture subsystem on the HC12: Latch time of an external event into a register, set a flag when event occurs, and generate an interrupt

19. Wednesday 2/28

    • Using DBug12 to print to the terminal
    • Figures
      • Using the DBug-12 printf routine to print information to the terminal
    • More on the HC12 Input Capture Subsystem
    • M68HC12 Family Manual, Section 12
      • Registers which need to be set up to use input capture subsystem (Part 1 of 3)
      • Registers which need to be set up to use input capture subsystem (Part 2 of 3)
      • Registers which need to be set up to use input capture subsystem (Part 3 of 3)
      • Program to measure the time between two rising edges using the HC12 Input Capture subsystem
      • Using the volatile keyword in C programs using interrupts

20. Friday 3/2

    • 68HC12 Output Compare function
    • M68HC12 Family Manual, Section 12
    • Figures
      • How would you use the HC12 to generate a pulse of a fixed length?
      • Generating a pulse using compares
      • Simplified diagram of the HC12 Output Compare function
      • Registers which need to be set up to use the Output Compare subsystem (Part 1 of 3)
      • Registers which need to be set up to use the Output Compare subsystem (Part 2 of 3)
      • Registers which need to be set up to use the Output Compare subsystem (Part 3 of 3)
      • Using the HC12 Output Compare function to generate a square wave
      • C program to generate a 1 kHz square wave using the Output Compare function
      • Using the HC12 Output Compare function

21. Monday 3/5

    • The HC12 Pulse Width Modulation System
    • M68HC12 Family Manual, Section 11
    • Figures
      • Pulse width modulation - control the speed of a motor by adjusting the duty cycle of a periodic signal
      • Many possible ways to implement PWM
      • We will use 8-bit, left-aligned, high polarity PWM
      • Registers used to set up the PWM - Part 1 of 2
      • Registers used to set up the PWM - Part 2 of 2
      • Need to decide on clock source, period and duty cycle of PWM, and enable PWM
      • Four possible sources for clock into PWM channels
      • Setting PWM period and duty cycle
      • Selecting a clock source and the PWM period register to get a desired PWM frequency
      • Register setup guidelines for using the HC12 PWM subsytem

22. Wednesday 3/7

    • More on the HC12 Pulse Width Modulation System
    • M68HC12 Family Manual, Section 11
    • Figures
      • C program for using the PWM subsystem

23. Friday 3/9

    • External Data Buses -- Talking to the Outside World
    • Figures
      • The HC12 is a Princeton architecture computer -- it talks to a single memory space over address, data and control lines
      • A computer talks to the outside world over address and data buses
      • The HC12 has a 16-bit address bus and a 16-bit data bus
      • Simplified example of what happens on the buses during the execution of a simple program
      • Example of reading from an external address
      • Example of writing to an external address
      • To have 16-bit address and data buses requires a large number of pins
      • To save pins the HC12 multiplexes the address and data buses. In expanded mode the HC12 uses Ports A and B as multiplexed address and data buses, so Ports A and B are not available for general purpose I/O. Example of bus activity on the multiplexed address/data bus during a write to an external location
      • External memory needs separate address and data buses
      • To use HC12 with external memory, need to demulitplex address and data buses -- use a latch to hold address when bus changes to data

24. Monday 3/19

    • More on the HC12 in Expanded Mode
    • Figures
      • Normally HC12 access 16 bits (two bytes) in a single memory cycle -- a byte at an even address and a byte at the next odd address
      • Somtimes the HC12 accesses a single byte at an even address
      • Somtimes the HC12 accesses a single byte at an odd address
      • The HC12 uses the LSTRB line together with the least significant bit of the address bus to specify whether it is accessing two bytes at a time, one byte at an even address, or one byte at an odd address
      • If A0 is low, the HC12 is accessing an even (upper) byte. If LSTRB is low, the HC12 is accessing an odd (lower) byte.
      • The internal addresses accessed by the HC12
      • We will use the block of memory between 0x1000 and 0x7fff for our external memory.
      • How to generate the control lines needed for the external memory chip.
      • The final hardware for the external memory expansion.

25. Wednesday 3/21

    • More on the HC12 in Expanded Mode
    • Figures
      • In expanded mode, the HC12 uses Ports A and B as a multiplexed address/data bus
      • How to distinguish between even (upper) and odd (low) bytes in the HC12 expanded mode
      • Using A0 and LSTRB to determine when the HC12 is accessing an even (upper) byte and/or an odd (lower) byte
      • Things to do to implement an input port
      • An 8-bit input port at address 0x0400
      • Things to do to implement an output port
      • An 8-bit output port at address 0x0401
      • Things to do to implement an input and output port
      • An 8-bit input/output port at address 0x0400, with the ability to read what was written to the port

26. Friday 3/23

    • Putting the HC12 into expanded wide mode
    • Figures
      • When the HC12 starts, it reads MODA and MODB to decide which mode to enter. We will start in single-chip mode, then write the mode register to go into expanded wide
      • When reset, several lines we need for expanded mode are not driven externally. We need to write the PEAR register to enable these lines, and need to write the MISC register to add an E-clock strech
    • Altera files for memory expansion
    • Figures
      • GDF file for added ports and memory expansion
      • GDF block for memory expansion
      • GDF block for added ports
      • TDF block for reading from address 0x0400
      • TDF block for writing to address 0x0400
      • Simulation of memory and port expansion

    • Monday 3/26

      • Using standard MSI logic for port expansion
      • Figures
        • Memory map of HC12 before adding external memory or ports.
        • Memory map of HC12 after adding external memory and ports at 0x400, 0x401, 0x402.
        • A 74HC138 decoder chip is often used form memory decoding in micropocessor expansion
        • Using address lines and E clock from the HC12 allow the 74HC138 to select different regions of memory
        • Using A15-A11 and E allow 74HC138 to select 8 different memory blocks in address range 0x0000 - 0x3fff
        • Using MSI logic to make an 8-bit output port. This output port will be selected for a write to any even address in the range 0x7800 to 0x7fff
        • Using MSI logic to make an 8-bit output port. This output port uses more address lines, and will be selected for a write to any even address in the range 0x0600 to 0x07ff
        • Using MSI logic to make an 8-bit input port and an 8-bit output port.

    • Wednesday 3/28

      • Review for Exam 2
      • Figures
        • Review for Exam 2

    • Friday 3/30

      • Exam 2

    • Monday 4/2

      • Expansion mode timing (M68HC12 Family Manual, pp. 478-479)
      • Figures
        • Simplified multiplexed bus timing for the HC12
        • Timing specs for HC12 from M68HC12 Family Manual, pp 478-479.
        • Technically, cannot run HC12 in expanded mode at 8 MHz -- address not on bus soon enough. However, will work in most cases.
        • Simplified timing for HC12 write.
        • Timing for a simple output port with glue logic.
        • Simplified timing for HC12 read.
        • Timing for a simple input port with glue logic.
        • Timing for the 12 ns memory chip used in the memory expansion project.

    • Wednesday 4/4

      • Introduction to A/D (Analog to Digital) converters
      • Figures
        • The heart of a D/A converter is an op amp
        • An inverting op amp amplifier used to sum multiple input signals
        • Input resistances which differ in values by factors of two
        • A four-bit D/A converter - use switches to turn inputs on and off
        • The heart of many A/D converters - a comparator
        • A 3-bit flash A/D converter using comparators and resistors - fast but complicated for high-bit A/D converters
        • A simple, but slow, A/D converter using a D/A, comparator, counter and latch
        • A successive-approximation A/D converter - need N clock cycles for an N-bit A/D
        • A successive-approximation A/D converter with a track/hold amplifier to keep the voltage constant while the A/D conversion takes place
        • State diagram for a 4-bit successive-approximation register
        • Using the A/D converter in the HC12

    • Friday 4/6

      • More on the HC12 A/D Converter
      • Figures
        • Summary of how to program the HC12 A/D converter
        • A C program to use the HC12 A/D converter in 8-bit mode
        • A C program to use the HC12 A/D converter in 10-bit mode

    • Monday 4/9

      • Introduction to serial communications
      • Figures
        • Simple asynchronous parallel communication
        • Synchronous parallel communications -- use a clock to tell receiver when data is valid
        • Parallel communications using handshaking -- use two lines so both sender and receiver know when data has been transfered.
        • Serial communications -- transmit one bit at a time
        • Synchronous serial communications -- Use a clock to tell receiver when data is valid
        • The HC12 SPI -- Synchronous Peripheral Interface -- allows bi-directional synchronous serial communication
        • The HC12 SPI uses a shift register to shift data into and out of SPI

    • Wednesday 4/11

      • Using the HC12 Serial Peripheral Interface (SPI)
      • MC68HC912B Family Manual, Section 14.4
      • Figures
        • Using the HC12 SPI with more than one slave
        • Setting up the SPI clock
        • Setting up the HC12 SPI
        • Guidelines for using the HC12 SPI
        • A C program for using the SPI in master mode

    • Monday 4/16

      • Connecting a MAX522 D/A converter to the HC12 SPI
      • Figures
        • Data sheet for the Maxim MAX522 D/A Converter
        • How to connect the MAX522 to the HC12
        • Program for using the MAX522 with the HC12

    • Wednesday 4/18

      • Review for Exam 3
      • Figures
        • Review for Exam 3

    • Friday 4/20

      • Exam 2

    • Monday 4/23

      • Introduction to the Motor Control Lab
      • Figures
        • Hardware setup for the final lab
        • Proportional speed control -- effects of the proportionality constant k
        • Program outline for the final lab