University of Florida EEL 4744 Spring 2012 Dr. Eric M. Schwartz Department of Electrical & Computer Engineering 22 February Jun-12 4:55 PM

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You may use any of your TI documents with limited added material; highlighting and tagging is permissible.

1 Page 1/13 Exam 1 Instructions: Turn off cell phones beepers and other noise making devices. Show all work on the front of the test papers. If you need more room make a clearly indicated note on the front of the page "MORE ON BACK" and use the back. The back of the page will not be graded without an indication on the front. You may use any of your TI documents with limited added material; highlighting and tagging is permissible. You may not use any notes (mine or yours) examples homework labs books calculators computer electronic devices etc. Put your name at the top of each test page and be sure your exam consists of 13 distinct pages. The space provided does not necessarily represent the amount of writing necessary. Relax! You must pledge and sign this page in order for a grade to be assigned. I n programs the use of comments results in more partial credit. May the Schwartz Read each question carefully and follow the instructions. The point values for problems may be changed at prof s discretion. be with you! Part of your grade on tests quizzes labs etc. is based not only on solving the problem you are presented with but the manner in which you solve it. For example there is a difference between two programs that meet the given specifications but one is an elegant extensible 20-line solution while the other is an obfuscated 100-line program that also meets the specifications but would be difficult to extend later. Just as your future employer would value the latter program less than the first so will I in grading your assignments. This exam counts for % of your total grade. Unless otherwise stated assume the following: Go Good The oscillator frequency is precisely 15 MHz. The code should run on a TMS320F2335 as configure on the UF F2335 Development Board without any additional peripherals. Gators! luck! You may assume all the bit.sets that you may need have already been done; use the standard I have used in class (e.g. BIT0 = b BIT76 = b INV7 = b INV15_6 = b). PLEDGE: On my honor as a University of Florida student I certify that I have neither given nor received any aid on this examination nor I have seen anyone else do so. PRINT YOUR NAME SIGN YOUR NAME DATE (22 Feb 12) Regrade comments below. Give page # & problem # and reason for the petition. Pages Available Points TOTAL 100

2 Page 2/13 Exam 1 [%] 1. Assume that you have a keypad circuit wired up as shown below. (3%) a) If O 2 is high and O 1 and O 0 are low explain what happens if the 4 and 7 keys are pressed at the same time. If this is a problem explain a possible circuit design change correct the problem. (3%) b) If O 2 is high and O 1 and O 0 are low explain what happens if the 7 and keys are pressed at the same time. If this is a problem explain a possible circuit design change correct the problem. (2%) c) Real switches bounce when they are activated or deactivated. Explain by drawing a circuit or explaining an algorithm to deal with switch bouncing.

3 Page 3/13 Exam 1 [%] 2. Write a program fragment (not an entire program) to set bit 4 in SRAM location FixIt (at 0xA025) if bit 4 of SRAM location CheckBits (at 0xA037) is 0 (i.e. clear); clear bit 2 at min FixIt if bit 2 at CheckBits is 1 (i.e. set). No other bits in either FixIt or CheckBits should be changed. Use of assembler directives is strongly encouraged. Labels Instructions Comments

Page 4/13 Exam 1 2. (continued) Labels Instructions Comments [5%] 3. Show the proper component placement for a switch circuit that will provide 4 inputs for your processor.

4 Page 4/13 Exam 1 2. (continued) Labels Instructions Comments [5%] 3. Show the proper component placement for a switch circuit that will provide 4 inputs for your processor. Use a 4-switch DIP component and all the other necessary components on your 5 min UF F2335 Development Board as you would with (only) the parts you were given in lab. Show the required wiring for each of the switches. Label the processor input from your switch circuits X 0 through X 3. Label the wires that are soldered those that are wirewrapped and those that are part of the printed circuit board (PCB). Use pull-down resistors if necessary.

5 Page 5/13 Exam 1 [15%] 4. Write a complete program to make GPIO25 an input GPIO26 an output and GPIO27 the 1 Enhanced Capture input/output 4 (ECAP4). Do NOT change the function of any of the other GPIO and do NOT corrupt any GPIO outputs. Read GPIO25; if it is clear complement the value of GPIO26; otherwise do not change GPIO26. This function should repeat forever! Labels Instructions Comments

6 Page 6/13 Exam 1 4. (continued) Labels Instructions Comments

7 Page 7/13 Exam 1 [23%] 5. Answer the following short questions. (2%) a) What device (be specific) is needed to add an output port to a microprocessor? Why? 1 min (4%) b) Addresses 0x through 0x2F FFFF (and other address ranges) are available for 4 min external interfacing on your F2335. Your F2335 has 22 address pins. Provide the equation for addresses (ignore control signals) that can be used to place a single output port at 0x through 0x13 FFFF. How many images (also known as aliases) are there for your output port? For full credit provide a single number not an expression. (2%) c) What do the.lst files show that the.asm files do not show? (2%) d) When a branch instruction (operation/mnemonic: B) condition is true how does the processor determine the correct destination? (2%) e) On which register(s) does the CPU depend in order to make branching decisions? 1 min

8 Page /13 Exam 1 5. (continued) (2%) f) What is the difference between.set and.word? When and for what should each be used? (2%) g) What is the difference between.word and.bss? When and for what should each be used? (2%) h) Why does the DSP forget your program when power is removed? 1 min (2%) i) What is the difference between an emulator and simulator? (2%) j) What is an advantage and disadvantage of partial address decoding? 1 min (1%) k) What system should be used to automatically reset the processor when it gets lost (i.e. blue screen of death ). 1 min

9 Page 9/13 Exam 1 [12%] 6. In this problem you will write a complete program to copy the characters in a table at 0xA100 (InTable) until the null character (0x00) is reached to a table at 0xB200 (OutTable). Any upper case characters should be converted to lower case characters but all other characters should be copied unchanged. The ASCII codes of A is 0x41 Z is 0x5A a is 0x61 and z is 0x7A. A subroutine (NoScream) will do the required conversion. Some of the key components of your program are described below. ( %) a) Write the assembler directives to put the input table at 0xA100 (InTable). Assume that eventually this table may be placed at another location in FLASH. Be sure to put the proper section instruction. Use the example input table data: In All KINDS OF WEATHER. Be sure to terminate the table with a null character. ( %) b) Write the assembler directives to put the output table at 0xB200 (OutTable). Be sure to put the proper section instruction. ( %) c) Complete the main routine and write a subroutine NoScream to do the required 10 min conversion. The main routine should initialize all values as necessary and terminate properly. (The next page is also available for your program.) Labels Instructions Comments

10 Page 10/13 Exam 1 6. (continued) Labels Instructions Comments

Initialize the stack pointer at an appropriate location in internal F2335 SRAM.

11 Page 11/13 Exam 1 [10%] 7. Assume a F2335 subroutine named Sub_Exam1 is located at address 0x9ABC. Write 10 min sample instruction(s) at address 0x9370 for appropriately executing a subroutine in the box below (left). Write the stack pointer initialization instruction(s) in the box below (right). Initialize the stack pointer at an appropriate location in internal F2335 SRAM. Address 0x9370 Subroutine execute instruction Stack pointer initialization Describe the stack on the F2335 as it relates to a subroutine. For each of the below descriptions draw the stack. In each case show an arrow () at the location of the stack pointer. On the far left show (valid) addresses for each of the used stack locations. Also provide the values requested at the bottom of these tables. 1) after the stack is initialized 2) at the start of the subroutine execution 3) after a push ACC instruction (ACC=0x D) 4) after a pop AR1 instruction 5) after the return from the subroutine 6) after a pop AR2 instruction immediately following subroutine execution instruction Address 1-After Init 2- Just after call 3-After push ACC 4-After pop AR1 5-After return 6-After pop AR2 AR1 = PC = AR2 =

Page 12/13 Exam 1 [15%]. The UF4744 is a new microcontroller 3 min very much like the 6HC11 6HC12 Atmel microcontrollers and your DSP discussed in class. Some relevant differences are discussed here.

12 Page 12/13 Exam 1 [15%]. The UF4744 is a new microcontroller 3 min very much like the 6HC11 6HC12 Atmel microcontrollers and your DSP discussed in class. Some relevant differences are discussed here. The same diagram timing diagram can be used for both Read and Write cycles with the only difference being the value of R/~W. The UF4744 has a time-multiplexed address/data bus. Reset (not shown) is active-low for this device. ( ) a) Circle all the critical times on the Read Cycle and Write Cycle diagrams. ( ) b) The entire address range of 3 min 0x0000 through 0x7FFF is available; the address range of 0x000 through 0xFFFF is unavailable. Add a 4k x SRAM starting at address 0 and an k x ROM at addresses starting immediately after the RAM. Fill in the blanks below to help you solve this problem. What equations would you use to control what signals for the SRAM and ROM. ( ) 3 min c) Add an -bit input and an -bit output port. Use partial address decoding to add these ports at address 0x4000 (with higher address images/aliases as necessary). Fill in the blanks below to help you solve this problem. What equations would you use to control what device(s) for an -bit input port and an -bit output port. 4K SRAM Addr Range: 0x0000-0x = B - B K ROM Addr Range: 0x - 0x = B - B InPort/OutPort Addr Range: 0x4000-0x = B - B Equations: SRAM: ROM: InPort: OutPort:

11 min D 7-0 G -bit Latch Q 7-0 D 7-0 G -bit Latch

13 Page 13/13 Exam 1 ( %). d) Complete the circuit diagram below in order to add the two ports and memory devices. Please USE LABELS instead of wires! Please USE LABELS instead of wires! 11 min D 7-0 G -bit Latch Q 7-0 D 7-0 G -bit Latch Q 7-0 -bit Flip-Flop D 7 -D 0 Q 7 -Q 0 -bit Flip-Flop D 7 -D 0 Q 7 -Q 0

University of Florida EEL 4744 Spring 2011 Dr. Eric M. Schwartz Department of Electrical & Computer Engineering 31 March Apr-11 1:29 PM

University of Florida EEL 4744 Spring 2011 Dr. Eric M. Schwartz Department of Electrical & Computer Engineering 31 March Apr-11 1:29 PM University of Florida EE 4744 Spring 2011 Dr. Eric M. Schwartz Page 1/15 Exam 2 Go Gators! Instructions: Turn off cell phones beepers and other noise making devices. Show all work on the front of the test