Final Examination Solutions Fall 2010

PwnHero Final Examination COE-538 / BME-538 - Microprocessor Systems December 11, 2010 Name: _____________________________________ Student #: _________________________ Time limit: 3 hours Examiners: K. Clowes, V. Geurkov Notes: a) Closed book. b) No calculators allowed. c) No questions during exam period. State any assumptions. d) Answer neatly all questions. Unclear answers will not be accepted. e) For each question, show the process that is used to derive the answer. f) Circle your professor’s name and hand in these sheets. 1. Short Answer Questions: [1 mark each] a) What makes a microcontroller different from a microprocessor? A microcontroller is a single chip that combines the microprocessor core and other peripheral functions such as timers, serial interface, parallel ports, ADC, etc. b) Convert 4K to decimal representation. 4K = 4 × 210 = 4 × 1024 = 4096 c) What is the last instruction in an interrupt service routine and what does it do? The last instruction in an interrupt service routine is RTI. This instruction restores all the CPU registers from the stack and also restores the PC from the stack so that the interrupted program can be restarted. d) How many locations are contained in the memory space $2000-$29FF? 10 × 16 × 16 = 2560 e) What HCS12 instruction is used to disable all maskable interrupts? SEI f) What is the most common way to clear flag bits in the HCS12? The most common way to clear flag bits is writing 1 into them. PwnHero.com