CSE477 Laboratory Assignment #1

Introduction to the M68HC11EVB: Using the Evaluation Board to Debug Microcontroller Programs

Assigned: 5 January
Due: 16 January

Objectives:

When you have completed this lab, you should know how to:

Power up your evaluation board and connect it to an NT machine,
Enter and debug simple assembly language programs using the monitor program on the evaluation board,
Download S-records generated by an assembler from an assembly language program,
Use a microcontroller to output a digital signal.
Enter and debug simple C language programs using the monitor program on the evaluation board.
Familiarization with the counter/timer unit of the 68HC11 microcontroller,
Use most of its input capture and output compare facilities,
Use basic interrupt handling capabilities, and
Understand the structure of data conversion routines.

Reading:

Chapters 1, 2, and 3 of the Jones/Flynn text.

Chapters 5, 6, 7, and 10 of the M68HC11 Reference Manual.

"Introduction to 6811 Programming" by Martin.

Part 1: Powering up the EVB and connecting it to the PC

You will need to supply power to the evaluation board through the power supply connected to your protoboard. Four lines are needed: +12, -12, +5, and GND. The supply lines are clearly marked on the power supply name plate and the EVB. Make sure they are connected properly before plugging in the power supply. GND and +5 are used to power the microcontroller and other digital circuitry on the board. The +12 and -12 supplies are used for the RS-232 logic levels. (If you exchange +12 and -12, or +12 and +5, or even +5 and GND, some damage will occur to the EVB. Don't do this. You will be responsible for this sort of damage.)

The serial line from the PC should be connected to the terminal port on the EVB (the RS-232 connector furthest away from the red reset button, this is marked terminal on the PCB) To communicate with the EVB, run hyper_terminal. From the drop down menu choose File->New connection. A "connection description" window appears, give a name for the connection, click OK. A "connect to" window appears, on box "connecting using" choose com1 or com2 depending up on the connection, click OK. A "property" window appears, in this choose the baud rate to be 9600, click OK. Now a connection under the above name is created.

Now plug in the power supply, and press the red reset button on the EVB. A prompt should be sent to the terminal program and displayed on the PC's screen. It should read:

BUFFALO 2.5 (ext) - Bit User Fast Friendly Aid to Logical Operation

Pressing return twice should list a bunch on commands that the EVB and BUFFALO can be asked to perform.

Part 2: BUFFALO Tutorial

Read Section 4.7 of your EVB user manual. Type in the assembly code on pages 4-27 and 4-28. Then issue the commands lists on page 4-29. (Remember to connect Pins 20 and 21 together on connector P1. This connects the TxD and the RxD lines of the SCI together. The example program will not work correctly if this connection is not made.)

Part 3: Assembly Language Program

Devise an assembly language program to turn a port bit on and off with a cycle period of one second. I suggest using port bit PB0. To get started, download the following sample program to the EVB. It just turns on this port bit. Then modify it for your needs. Make sure that there is a tab before each of the instructions below.

        ORG $C000
        LDAA #$01
        STAA $1004

Type this program in using notepad and run the assembler that is located at U:\cse477\buffalo\as11.exe. (U should be mapped to \\ifilesrv1\courses) Run the assembler using the file manager's RUN command and the assembly program's name as its only argument. To load the assembled file to the EVB, you need to perform a text transfer using the terminal emulator. First type

        LOAD T

at the BUFFALO prompt and then pull down the Transfers->Send Text File panel. Select the file generated by the assembler (it has the extension .S19) and click the OK button. Your program should now be loaded into the EVB. Press the red reset button to restart BUFFALO. (Note: its not clear why you need to reset in order to start running the program but this seesm to be the only way to get things to work.)

To actually run these two instructions, first set a breakpoint after the last instruction (use the BR C005 command) and then enter G C000. You should be able to observe that PB0 is now set to 1 with your logic probe. The other bits of port B should all have been cleared to a logic 0.

Part 4: C Language Program

Read the information from a previous quarter's cse477 project. The SmallC compiler project will help you get started in compiling and running simple C programs. You need to work through the following sections of C language code. Part 1, Part 2, and Part 3 are the C code fragments that you need to run. The corresponding assembly code is a little difficult to follow at first, but can also be ran. "EX10.asm" is the assembly file you will need to run. If you start by working through the assembly code and understand how the microcontroller is executing the assembly, then following the corresponding C language code will be very easy to understand. However, you are free to start with the C code and not spend much time looking at assembly if you choose. Knowing the assembly is not required for this part of the lab. To find a description of assembly code look at the lab assignment from last spring and it's description of the file "EX10.asm".

Part 1 demonstrates measuring long periods using interrupts and the Timer Over Flow interrupt handler.
Part 2 requires the user to enter a half-cycle delay at $D000 and $D001 using memory modify (MM) before the program is executed. The output compare function is handled with interrupts. Compare how this is done both in the C program and in the assembly program.
Part 3 produces two pulse width modulated signals. It also requires the user to set three values before executing the program. It's important to note that OC1 is used to schedule and time signals out of OC2 and OC3. However, OC2 and OC3 control their own output levels.

What to Turn In

Turn in the assembly program that makes the port bit turn on and off with a cycle period of one second.
Demonstrate the execution of the C programs to the TA. Please make sure to allow time for this.

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