University of Florida EEL 4744 Fall 1998 Dr. Eric M. Schwartz

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1 Department of Electrical & Computer Engineering 15 October 199 Professor in ECE 31-Dec-9 12:22 PM Page 1/ Instructions: 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 our Programming Reference Guide (Bible). You may not use any notes, homework, labs, other books, or calculators. Put your name at the top of each test page and be sure your exam consists of distinct pages. The space provided does not necessarily represent the amount of writing necessary. You must pledge and sign this page in order for a grade to be assigned. In programs, the use of comments results in more partial credit. Read each question carefully and follow the instructions. This exam counts for 20% of your total grade. Good luck! Unless otherwise stated assume the following: The oscillator frequency is precisely MHz. The code should run on a MC6HC11E9 with 64k of external RAM and without BUFFALO but with ROM, EEPROM, RAM and Registers as defined in the Bible. You may assume all internal register equates (at $1000 $103F, e.g., PORTB EQU $1004 or PORTB EQU $0004 all of the former or all of the later) and all the bit equates that you may need (e.g., BIT0 EQU % , BIT76 EQU % , INV7 EQU % ) are already done. 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 COMMENTS, FEEDBACK, or any special instructions for the professor: Problem Available Points 1a 40 1b 25 2a 4 2b 2c 22 TOTAL While you are waiting for the exam to begin, please fix the following in the bible you have in front of you: TOI bit of TMSK2 on page 63 should read: 0 = TOF interrupts disabled. Mnemonic Boolean Expression BCLR (M) mm (M) BRCLR? (M) mm = 0 BRSET? (M) mm = 0

2 Department of Electrical & Computer Engineering 15 October 199 Professor in ECE 31-Dec-9 12:22 PM Page 2/ [65%] 1. An X-Caliber5005 LCD (liquid crystal display) must be driven with a min 6HC11. Memory-map the LCD to the two locations $C000 and $C00, 9 where the first address is for commands, and the second is for data. No other devices exist in the memory-mapped space from $C000-$CFFF. The ! 3 LCD can display ASCII characters in 64 display positions (shown to the right). 63 There are four possible commands for C=C000 / D=C00 this LCD: Write, Read, Clear and CMD Display Position Complement. These commands are Command (CMD) encoded in the most significant 2-bits of Clear 0 0 a one-byte command word. The lower Read bits of the command word specifies Write 1 0 the appropriate LCD display position. Complement 1 1 To write! to position 37=$25, for example: First send (write) the command $A5 (since a write command has %10 in bits 7 and 6). Write this byte to location $C000. Next send (write) the ASCII code for! (see bible page 71) of $21. Write this byte to location $C00. C=C000 / D=C00 CMD Display Position Command (CMD) Write example $A Read example $ To read from position 37=$25, for example: First send (write) the command $65 (since a read command has %01 in bits 7 and 6) to location $C000 Next read the ASCII code at location $C00. The Clear and Complement commands require no data, and respectively blank or invert the colors of a particular LCD character position. The CE, WR, and RD (sometimes called OE) operate identically to the same pins on the RAM used in lab. There is one additional control line C/~D (command/data) that tells the LCD whether the information on its data lines is a command (when high) or data (when low). On the next 2 pages, you will design a circuit (no PAL allowed) to connect the microcontroller with the X-Caliber5005 and create a subroutine to fill the LCD with characters. X-Caliber505 LCD C/~D D7 -D WR 0 RD CE

3 Department of Electrical & Computer Engineering 15 October 199 Professor in ECE 31-Dec-9 12:22 PM Page 3/ (40%) 1. a) Design the circuit on this page. Some possibly useful parts have been given below, but feel 15 min free to add others 74XXX-type chips or gates that you may need. It is not necessary to give the chip numbers. You are encouraged to use mixed-logic and to use labels instead of wires (as in LogicWorks ). You must incorporate RESET in your design to protect the LCD from inadvertent changes during reset. -bit Flip-Flop D 7 -D 0 CLK Q 7 -Q 0 -bit Tri-State In 7-0 Out 7-0 OE X-Caliber505 LCD C/~D D7 -D WR 0 RD PC 7-0 = AD 7-0 PB 7-0 =A 15- XIRQ IRQ R R/~W W E AS Reset 6HC11 PA 7 -PA 0 PD 5 -PD 0 PE 7 -PE 0 D 7 -D 0 G CE -bit Latch Q 7 -Q 0 74HC13 X 2 X 1 X 0 CE 1 CE 2A CE 2B Y 0 Y 1 Y 2 Y 3 Y 4 Y 5 Y 6 Y 7

4 Department of Electrical & Computer Engineering 15 October 199 Professor in ECE 31-Dec-9 12:22 PM Page 4/ (25%) 1. b) Write a subroutine that copies a 15 min variable number of bytes from a table at a variable location in memory to the LCD display starting in position 0. These variables are passed into the subroutine as shown in the sample calling sequence, where the table is 1 C=C000 / D=C00 CMD Display Position Command (CMD) Clear 0 0 Read 0 1 Write 1 0 Complement 1 1 bytes long and begins at $2E00. For this example, your subroutine should modify the first 1 display positions on the LCD. You must cleanup the stack before completing the subroutine. If you need any special variables or equates, write those below the subroutine. Labels Instructions Comments OUT_LCD LDX #$2E00 PSHX LDAA #1 JSR OUT_LCD

5 Department of Electrical & Computer Engineering 15 October 199 Professor in ECE 31-Dec-9 12:22 PM Page 5/ [34%] 2. The 6HC11 has a built-in UART (Universal Asynchronous Receiver/Transmitter) system called SCI. For this problem, we are going to use an external UART to send serial data to a 5 min Robot Information Controller (RIC). The HC11 is in single-chip mode. The HC11 presents -bit parallel data (P 7-0 ) to the UART and the UART (with some other control signals not defined here) automatically serially shifts the data (S) out to RIC at the appropriate rate. When RIC needs more data, always in 256 byte blocks, it sends an active-low request pulse (REQ) to the HC11, i.e., REQ is normally high and RIC will generate a 1µs low pulse when more data is needed. Since eventually the HC11 will have an additional primary purpose, the request must not be checked by polling. Upon receiving a request for a data block, the HC11 must send out one byte every 16ms (±10%) until 256 bytes have been sent from a table starting at memory location $3700. You may not use a timing loop to generate the 16ms PC 7-0 = AD 7-0 PB 7-0 =A 15- XIRQ IRQ R R/~W W E AS Reset 6HC11 PA 7 -PA 0 PD 5 -PD 0 PE 7 -PE 0 UART Parallel data Serial data P 7-0 from HC11 from HC11 REQ Request for data S Robot Info Controller (RIC) delays. (4%) a) Add the necessary 2 connections to the 6HC11 above. Explain how you intend to solve 5 min this problem, i.e., describe the systems, ports and interrupts you will use and why you made these choices. (This will help the grader determine what you were trying to do and force you to think before you write.)

6 Department of Electrical & Computer Engineering 15 October 199 Professor in ECE 31-Dec-9 12:22 PM Page 6/ (%) 2. b) Based on the above description, give the entire main routine, and initializations here. 10 min You may need to come back to this after working on the next part. The last line of the main routine must be: HERE: BRA HERE Some Details: Write the initializations necessary for the problem described above. This will include assembler directives and a complete program. Initialize variables, pins, systems, interrupt(s), etc. as needed. Labels Instructions Comments HERE: BRA HERE

7 Department of Electrical & Computer Engineering 15 October 199 Professor in ECE 31-Dec-9 12:22 PM Page 7/ (22%) 2. c) Write the interrupt service routine(s) and/or subroutine(s) needed to complete this problem. The next page is provided to complete this code. 15 min Labels Instructions Comments

8 Department of Electrical & Computer Engineering 15 October 199 Professor in ECE 31-Dec-9 12:22 PM Page / (0%) 3. c) Continued. Labels Instructions Comments

Go Gators! Relax! May the Schwartz be with you!

Go Gators! Relax! May the Schwartz be with you! Page 1/12 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