Lecture Outline for Spring 2000

1. Wednesday 1/19

   • 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
   • Binary and hexadecimal numbers (Katz, Appendix A).
   • Figures
     • Binary, hex and decimal numbers
     • Converting unsigned binary numbers to decimal numbers
     • Converting unsigned hex numbers to decimal numbers

2. Friday 1/21

   • Signed and Unsigned Hex Numbers (Katz, Chapter 5)
   • Figures
     • Binary, hex and signed and unsigned decimal numbers
     • Converting decimal numbers to unsigned hex numbers - division
     • Converting decimal numbers to unsigned hex numbers - table
     • Hex numbers can have a variety of meanings depending on the context
     • 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
     • How to tell if an addition or subtraction generates an overflow

3. Monday 1/24

   • Signed and Unsigned Hex Numbers (Katz, Chapter 5)
   • Figures
     • Subtracting binary numbers: The carry and overflow bits
   • The HC12 Internal Registers (MC68HC912B32 Technical Summary, Section 2.1; CPU 12 Reference Manual, Section 2.1)
   • Figures
     • The HC12 has a 16-bit memory space, allowing access to 65,536 bytes of memory
     • Common memory types
     • Memory allocation in the 68HC12
     • You can use 512 bytes of RAM, from 0x0800 to 0x09FF
     • The control unit interprets instructions and tells the combinational Arithmetic Logic Unit what to do
     • A 16-bit program counter tells the control unit which instruction to execute next
     • The main registers in the HC12 are A and B, two eight-bit registers. The registers can be considered as a single 16-bit register named D
     • The full HC12 programming model: the A, B, X, Y, SP, PC, and CCR registers
     • A simple program for the HC12, loaded at address 0x0800, and using data from addresses 0x0900 and 0x0901
     • The same program using assembler directives, making the program easier to read by humans
     • How to assemble a program using the Cosmic assembler
     • Listing file generated by assembler for simple program

4. Wednesday 1/26

   • Addressing Modes (CPU 12 Reference Manual, Section 3)
   • Figures
     • Things you need to know for assembly language programming
     • HC12 Addressing Modes
     • Inherent (INH) Mode
     • 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

5. Friday 1/28

   • Assembly language programming on the 68HC12
   • Figures
     • Using assembler directives dc and ds
     • 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
     • 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

6. Monday 1/31

   • 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
   • 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

7. Wednesday 2/2

   • Review of carry and overflow
   • Figures
     • How to determine if the carry bit will be set
     • How to determine if the overflow bit will be set
   • 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

8. Friday 2/4

   • 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
   • 68HC12 Technical Summary, Section 6.2
   • Figures
     • Concept of an input port
     • Concept of an output port
     • How to use PORTA on the 68HC12

9. Monday 2/7

   • 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
     • Programming constructs in both assembly and C
     • Simple programs in both assembly and C

10. Wednesday 2/9

    • More on C programming on the 68HC12
    • Figures
      • A simple C program, and instructions for compiling
      • Flow chart for if-then construct
      • Flow chart for if-then-else construct
      • Flow chart for do-while construct
      • Flow chart for while construct
      • 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

11. Friday 2/11

    • More on C programming on the 68HC12
    • Figures
      • C Programming Basics
      • Setting and clearing bits in assembly and C
    • Introduction to the free-running timer on the 68HC12
    • 68HC12 Technical Summary, Pages 73-76
    • 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

12. Monday 2/14

    • More on the free-running timer on the 68HC12
    • 68HC12 Technical Summary, Pages 73-76
    • Figures
      • The 68HC12 16-bit timer - How to change the overflow rate
      • Setting and clearing bits in assembly and C
      • 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
    • What happens when you reset the 68HC12
    • 68HC12 Technical Summary, Section 9
    • Figures
      • Reseting the 68HC12

13. Wednesday 2/16

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

14. Friday 2/18

    • Exam 1

15. Monday 2/21

    • Introduction to Interrupts: The HC12 Timer Overflow Interrrupt
    • 68HC12 Technical Summary, Section 9
    • 68HC12 Technical Summary, Section 12
    • Figures
      • Introduction to Interrupts
      • Using interrupts on the HC12
      • Generating timer overflow interrupts
      • Interrupt vectors, registers and stack before receiving a timer overflow interrupt
      • Interrupt vectors, registers and stack after receiving a timer overflow interrupt

16. Wednesday 2/23

    • Interrupts: The HC12 Timer Overflow Interrrupt and Real Time Interrupt
    • 68HC12 Technical Summary, Section 9
    • 68HC12 Technical Summary, Section 10
    • 68HC12 Technical Summary, Section 12
    • Figures
      • What happens when the HC12 gets an unmasked interrupt
      • Two ways to generate a periodic interrupt: Timer Overflow and Real Time Interrupt
      • Interrupt rates for TOI and RTI
    • Introduction to the HC12 Input Capture Subsystem
    • 68HC12 Technical Summary, 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
      • Program to measure the time between two rising edges using the HC12 Input Capture subsystem
      • Considerations for setting and clearing bits in the timer subsystem, and clearing flags in the timer subsystem

17. Friday 2/25

    • Interrupts: Review of timer overflow, real time interrupt, and input capture
    • 68HC12 Technical Summary, Section 10
    • 68HC12 Technical Summary, Section 12
    • Figures
      • Program using both the timer overflow and real time interrupts
      • Procedure for using the input capture function of the HC12
      • Measuring the time between two edges using the input capture function, and printing the information to the screen

18. Monday 2/28

    • Using DBug12 to print to the terminal
    • Figures
      • Using the DBug-12 printf routine to print information to the terminal
    • 68HC12 Output Compare function
    • 68HC12 Technical Summary, Section 12
    • Figures
      • Functions of the HC12 timer subsystem
      • How would you use the HC12 to generate a square wave?
      • Simplified diagram of the HC12 Output Compare function
      • 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

19. Wednesday 3/1

    • The HC12 Pulse Width Modulation System
    • 68HC12 Technical Summary, 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
      • 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
      • C program for using the PWM subsystem

20. Friday 3/3

    • External Data Buses -- Talking to the Outside World
    • Figures
      • 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

21. Monday 3/6

    • More on the HC12 in Expanded Mode
    • Figures
      • 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
      • 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

22. Wednesday 3/8

    • Guidelines for setting up the HC12 PWM registers
    • Figures
      • Some guidelines for setting up the HC12 PWM registers
      • More on the HC12 in Expanded Mode
      • Figures
        • How to access odd and even bytes in HC12 expanded mode
        • An 8-bit input port at address 0x0400
        • An 8-bit output port at address 0x0400, with the ability to read what was written to the port
        • An 8-bit bidirectional port at address 0x0400, with the ability to read what was written to the port
        • Memory chips span many address locations
        • An address decoder to select 16 kB of memory at 0x4000 to 0x7fff
        • Connecting memory to the HC12 using the address decoder above

23. Friday 3/10

    • Bus timing on the HC12
    • MC68HC912B32 Electrical Characteristics Technical Supplement
    • Figures
      • HC12 timing when doing a read (from Technical Supplement)
      • Timing for reading from an external port (built into an Altera chip). Circled times are from the Technical Supplement
      • Timing for the 70 ns static RAMs used in lab
      • Timing does not work unless we slow down the HC12 -- need to add an E-clock stretch
    • Putting the HC12 into expanded wide mode
    • Figures
      • Memory map of HC12 in single-chip mode
      • Memory map of HC12 in expanded mode, after adding memory and ports
      • 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

24. Monday 3/20

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

25. Wednesday 3/22

    • Exam 2

26. Friday 3/24

    • Altera design for memory expansion and added ports
    • Figures
      • Altera GDF file for memory expansion
      • Altera GDF file for expansion port latches
      • Altera TDF file for generating a high signal when writing to address 0x0400 (Expanded Port A)
      • Top-level Altera GDF file for memory expansion and expanded ports
      • Altera TDF file for generating a high signal when reading from address 0x0400 (Expanded Port A)
      • Simulation of memory reads and writes using the above Altera design
      • Simulation of expanded port reads and writes using the above Altera design

27. Monday 3/27

    • How to get the HC12 into Expanded Wide mode (see material from 3/10 as well)
    • Figures
      • EEPROM start-up code to put the HC12 into expanded wide mode
    • Review of Altera desing from 3/24

28. Wednesday 3/29

    • Solutions to Exam 2

29. Friday 3/31

    • Using standard MSI logic for port expansion
    • Figures
      • 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
    • IRQ and XIRQ interrupts (H12 Technical Reference, Section 9)
    • Figures
      • Using an external signal to generate an interrupt on the IRQ and XIRQ pins of the HC12
      • A simple way to interface to the IRQ interrupt pin

30. Monday 4/3

    • Expansion mode timing (HC12 Electrical Characteristics Manual, pp. 14-15)
    • Figures
      • Timing for an output port using MSI logic -- the port will not work using HCMOS chips, will work with ALTERA or AHCMOS chips
    • Introduction to Serial Communications (HC12 Technical Summary Manual, Section 13)
    • Figures
      • Parallel communications - send 8 bits at a time - no way to tell when data is valid
      • Parallel communications - can use a clock to tell when data is valid
      • Parallel communications - can use handshaking to tell when data is valid
      • Serial communications - transmit one bit at a time - need way to tell when bit is valid
      • Serial communications - can use a clock to tell when data is valid - this is synchronous serial communications
      • The HC12 uses the Serial Peripheral Interface (SPI) for synchronous serial communications
      • Can communicate with multiple devices by use of Slave Select with the SPI
      • Simplified diagram of the SPI subsytem -- SP0DR is a shift register -- data is shifted out of and into SP0DR at the same time. Data written to SP0DR is shifted out to slave; data from slave is shifted into SP0DR

31. Wednesday 4/5

    • More on expansion mode timing (HC12 Electrical Characteristics Manual, pp. 14-15)
    • Figures
      • Start timing analysis by making sure you meet setup and hold times of device receiving the data
    • More on the HC12 Serial Peripheral Interface (SPI) (HC12 Technical Summary Manual, Section 13)
    • Figures
      • Four ways to set up clock on SPI
      • Setting up the HC12 SPI - program SP0CR1, SP0CR2, SP0BR and DDRS
      • SPI protocol for use with the MAX 522 D/A Converter -- need clock idle high, transfer on first edge
      • Maximum clock frequency for the MAX 522 is 5 MHz - will work with 4 MHz maximum frequency of HC12
      • To program MAX 522 need to transfer 16 bits with Slave Select low -- cannot use HC12 automatic slave select function

32. Friday 4/7

    • More on the HC12 Serial Peripheral Interface (SPI) (HC12 Technical Summary Manual, Section 13)
      Using the HC12 to control the MAX 522 D/A converter
    • Figures
      • General guidelines for using the HC12 SPI
      • C program to set up the HC12 SPI in master mode
      • C program to set up the HC12 SPI in slave mode
      • Block diagram of the MAX 522 D/A converter
      • Control register for the MAX 522 D/A/ -- how to enable and write to the two D/A converters
      • C program for using the MAX 522 D/A converter

33. Monday 4/10

    • Using the Maxim 522 D/A Converter Chip
    • Figures
      • How to determine analog voltage output for a digital input to the MAX 522
    • 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

34. Wednesday 4/12

    • The HC12 A/D converter
    • Figures
      • Block diagram of the HC12 A/D subsystem
      • How to use the HC12 A/D subsystem
      • Program to set up and use the HC12 A/D converter

35. Friday 4/14

    • Discussion of final lab project

36. Monday 4/17

    • Review for Exam 3

37. Wednesday 4/19

    • Exam 3

38. Monday 4/24

    • Solutions to Exam 3
    • More discussion of final lab project

39. Wednesday 4/26

    • More discussion of final lab project
    • HC12 Serial Communications Interface (SCI)
    • HC12 Technical Summary, Section 13.2
    • Figures
      • SCI has no external clock -- data is sychronized by common baud rate, start bit and stop bit
      • SCI transmit and receive shift registers are double-buffered
      • SCI uses clock 16xBaud, and checks for valid data at three places in the middle of the data bit
      • Registers used for the SCI

40. Friday 4/28

    • Other subsystems of the HC12
    • Figures
      • Pulse accumulator in event count mode -- can count number of pulses on Bit 7 of Port T
      • Pulse accumulator in gated time mode -- can count number of 125 kHz (P-clock divided by 64) clock pulses while signal on Bit 7 of Port T is high
      • Computer Operating Properly (COP) reset -- need to write correct sequence of bytes to COPRST register in specified time, or HC12 will reset
      • Byte Data Link Communications (BDLC) subsystem -- used for communication with devices in an automobile

41. Monday 5/1

    • Further discussion of SCI

42. Wednesday 5/3

    • Review for Final Exam
    • Figures
      • Review for Final Exam

43. Friday 5/5

    • Review for Final Exam
    • Figures
      • Review for Final Exam