Final Examination Fall 2005

PwnHero Ryerson University Department of Electrical and Computer Engineering COE538 – Microprocessor Systems Final Examination December 12, 2005 Name: _____________________________ Student #: __________________ Section: ________ Time limit: 3 hours Examiners: K. Clowes, V. Geurkov, A. Ye Notes: a) Closed book. b) No questions during exam period. State any assumptions. c) Answer Questions 1—6 and either Question 7 or Question 8. d) For each question, show the process that is used to derive the answer. e) Answer neatly all questions in the space provided. Unclear answers will not be accepted. f) Circle your professor’s name and hand in these sheets. 1. Short Answer Questions : a) What is the AS signal on the 68HC11 used for? [2 marks] b) Draw the rising edge and the falling edge of a digital signal. [2 marks] c) What is a soft interrupt vector? [2 marks] d) Describe the difference between pulse and interlocked handshaking. [2 marks] e) How is a flag bit in the 68HC11 timer module cleared? [2 marks] 2. Questions on Memory Organization: a) Suppose that the select inputs of a 3-8 decoder are connected in order to the address inputs A15- A13 of the 68HC11. Determine the address ranges controlled by O0 - O7. [2 marks] b) How many memory chips are required to build a 1MB, 16-bit wide memory system using 64K x 8 SRAM chips? Draw the layout of these SRAM chips. [3 marks] 3. Questions on SCI: a) Compute the time required to transmit 65 characters using the data format of eight data bits, one parity bit and two stop bits. The transmission speed is 2400 baud. [2 marks] b) Sketch the TxD pin output of a UART chip for the letter C (ASCII $43). The letter C is to be transmitted using a format with eight data bits, even parity, and one stop bit. [3 marks] PwnHero.com