CE-320 Microcomputers I Winter 2010 LAB 1: MINIIDE GROUP #: NAME: PARTNER: Lab 1 Page 1

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1 LAB 1: MINIIDE GROUP #: NAME: PARTNER: Lab 1 Page 1

2 LAB 1: MINIIDE GOALS Understand Wytec s Dragon12+ evaluation board Know how to use Dragon12 commands Understand an integrated development environment (IDE) Know how to use MiniIDE WHAT TO DEMONSTRATE/SUBMIT Completed figures. Answers to questions. INTRODUCTION This week s lab is intended to familiarize you with Wytec s Dragon12+ evaluation board and the MiniIDE interface program. The Dragon12+ board runs the monitor program D-Bug12 which uses a very standard set of commands to communicate with a PC using a serial port. Using MiniIDE, you will enter some simple machine language programs and some data into the Dragon12+ board and trace the execution of the programs. The assignment in the following section uses the D-Bug12 commands described in pages of the textbook (also available in MiniIDE). The assignment will tell you which commands to use, and the book gives examples of using each command. Page 86 shows a table that summarizes the instructions and may be useful in future weeks. Lab 1 Page 2

3 Summary of D-Bug12 commands DRAGON12+ EVALUATION BOARD This section gives a little background on the microprocessor board and establishing communication with it. 1. Double-check that the serial cable is plugged into the upper D-connector by the LCD screen and that the power jack is plugged in (If everyone is following directions, the serial cable should never be moved, but the power cord is often removed for long weekends). 2. Open MiniIDE by clicking on the desktop icon. 3. Verify that the terminal window is open. The Terminal window button in the menu bar should be highlighted. 4. Verify that the Terminal Connect/Disconnect button in the menu bar is highlighted. Lab 1 Page 3

4 5. Press the light blue RESET button on the Dragon12+ board, located along the bottom edge in the middle of the board. The 8 red LEDs should light up from left to right, and a DRAGON12plus message should appear on the LCD screen. Also, a D-Bug12 message should print to MiniIDE s terminal window. This terminal is used to send the commands to the evaluation board. ASSIGNMENT A program to add five numbers. Figure 1 shows an assembly language program and the corresponding machine code to add a list of five numbers beginning at address 1000h, and it stores the result in address 1008h. Code Memory Contents Assembly Code Line Address 1: 2000h B6 LDAA 1000h 2001h h 00 2: 2003h BB ADDA 1001h 2004h h 01 3: 2006h BB ADDA 1002h 2007h h 02 4: 2009h BB ADDA 1003h 200Ah Bh 03 5: 200Ch BB ADDA 1004h 200Dh Eh 04 6: 200Fh 7A STAA 1008h 2010h h 08 7: 2012h 3F STOP Figure 1 - Program to Add Five Numbers 1. Use the BF command to set locations 2000h to 2FFFh to all 00 s. 2. Use the MM command to enter each byte of machine code into the appropriate locations. Lab 1 Page 4

5 3. Use the MD command to display the entire program on the screen. Manually verify that the program has been entered correctly before continuing. 4. Use the MM command to enter the data values in Figure 2 in the appropriate locations. Memory Address 1000h 1001h 1002h 1003h 1004h 1008h Contents 3Ah 5Eh FEh 8Bh 56h 00h Figure 2 - Initial Data (Note: addresses are not consecutive) 5. Use the RM command (or similar) to set the A register to FFh. 6. Set each of the N, Z, V, and C bits to 0 (see Examples 3.8 on page 94 of the textbook). 7. Set the PC to 2000h using the RM command. 8. Use the RD command to verify the modified values of the registers. 9. Use the G command to run the program. 10. Use the MD command to examine the answer in location 1008h. QUESTION 1: What answer does the program calculate? QUESTION 2: If the numbers were added as unsigned bytes and the number of digits in the answer was not limited, what is the correct sum of the five numbers? 11. Repeat steps 4 through 8, then use the T command to trace the program s execution line by line and complete the program trace in Figure 3. Lab 1 Page 5

6 Recall that each line in the trace shows the register contents after that instruction has been executed. Trace Line Code Line PC A N Z V C Figure 3 - Program Trace QUESTION 3: The running sum in accumulator A may not have a valid value based on the value in the previous line and the number being added to it. Which trace lines contain invalid running sums in A if the numbers were unsigned? QUESTION 4: Which trace lines contain invalid running sums in A if the numbers were signed? QUESTION 5: Which condition code register bits correspond to the unsigned overflows and signed overflows in the lines from Questions 3 and 4? Circle one for each case. Unsigned overflow: N Z V C Signed overflow: N Z V C Lab 1 Page 6

7 A looping program to add five numbers. Figure 4 shows an assembly language program and the corresponding machine code. This program adds five numbers like the first program, but it uses a loop instead. Code Memory Contents Assembly Line Address 1: 2000h 87 CLRA 2: 2001h CE LDX #1000h 2002h h 00 3: 2004h C6 LDAB #5 2005h 05 4: 2006h 27 BEQ 06h 2007h 06 5: 2008h AB ADDA 0,X 2009h 00 6: 200Ah 08 INX 7: 200Bh 53 DECB 8: 200Ch 20 BRA Dh F8 9: 200Eh 6A STAA 3,X 200Fh 03 10: 2010h 3F STOP Figure 4 - Program to Add Five Numbers 1. Use the MM command to enter each byte of machine code into the appropriate locations. 2. Use the MD command to display the entire program on the screen. Manually verify that the program has been entered correctly before continuing. 3. Use the MM command to enter the data values in Figure 2 in the appropriate locations. 4. Use the RM command to set the A and B registers to FFh and the X register to FFFFh (Note that Debug-12 refers to the X register as IX to distinguish it from the X bit in the CCR register, and Y is called IY to match the convention used for the X register). 5. Set each of the N, Z, V, and C bits to 0 (see Examples 3.8 on page 94 of the textbook). 6. Set the PC to 2000h using the RM command. 7. Use the RD command to verify the modified values of the registers. 8. Use the G command to run the program. 9. Use the MD command to examine the answer in location 1008h. Lab 1 Page 7

8 10. Repeat steps 3 through 7, then use the T command to trace the program s execution line by line for the first 15 executed instructions and complete the program trace in Figure 5. Recall that each line in the trace should show the register contents after that instruction has been executed. Trace Line Code Line PC X A B N Z V C Figure 5 - Program Trace 11. Repeat steps 3 through 7, and then add a breakpoint at address 2006h using the BR command. 12. Run the program from the beginning. The address displayed in the PC should be the address at which you added a breakpoint in Step 11. Note that when the processor stops at a breakpoint, the instruction that the PC points to has not yet been executed. 13. Complete the breakpoint trace for Iteration 0 in Figure 6 based on the register values at the breakpoint. Lab 1 Page 8

9 14. Use the G command to proceed from the breakpoint and complete the remaining rows in Figure 6. You will need to use the G command several times. Do not proceed once the end of the program has been reached. Iteration PC X A B N Z V C Figure 6 - Breakpoint Trace 15. Repeat steps 3 through 7 and run the program again from the beginning. When it halts at the breakpoint, use the NOBR command to remove the breakpoint (This version of Debug-12 will not correctly trace through an instruction with a breakpoint). Trace the program with the command until address 2006h is reached again. QUESTION 6: Which trace lines of Figure 5 correspond to the lines that were just traced? 16. Continue execution with the G command. QUESTION 7: What address does the PC contain when execution halts? Lab 1 Page 9

10 QUESTION 8: Which lines of code in Figure 4 must be changed to write the sum to memory location 3008h? Also write a line (or lines) of the assembly program for it. QUESTION 9: Which lines of code in Figure 4 must be changed to add numbers beginning at memory location 3500h? Also write a line (or lines) of the assembly program for it. QUESTION 10: Which lines of code in Figure 4 must be changed to add numbers instead of 5? Also write a line (or lines) of the assembly program for it. Lab 1 Page 10