7ENT1112 Explain the sustainability factors in electronic design.
7ENT1112 Smart Embedded Systems Engineering - University of Hertfordshire
Laboratory Exercise:Power and Energy Efficiency in Embedded Systems
Learning Outcome 1: Understand appropriate techniques in smart and embedded systems engineering.
Learning Outcome 2: Explain the sustainability factors in electronic design.
Learning Outcome 3: Apply relevant technologies to smart embedded systems.
Learning Outcome 4: Implement smart embedded systems and evaluate their performance.The following 4 questions to be answered for the final submission of CW2.
Question 1. Assuming the main oscillator in an LPC1768 application is running at 16.000 MHz, the PLL multiplies by 8, and the lower 7 bits of register CCLKCFG are set to 5. What is the frequency of cclk?
Question 2. With the aid of a diagram describe the functions of the three clock sources within the LPC1768. (Word limit not more than 300)
Question 3. Propose and discuss practical situations where each of the LPC1768 low power modes (Sleep, Deep Sleep, Power Down and Deep Power Down) can be used effectively.
(Word limit not more than 500)
Question 4. Critically analysis dynamic voltage and frequency scaling; describe their principles and how they can be used to efficiently to reduce power consumption in embedded designs; compare and contrast them by analyzing their advantages and disadvantages; give practical examples in an embedded system context.
(This should not exceed 1000 words. Use numbered citations in your text, which should be between 2 and 5 citations.Figures and Tables can be used.)
Assignment Task 1. Changing the CPU Clock Divider settings
Compile and download Program Example 1 above to an mbed, first with the lineCCLKCFG=0x00000005;commented out. The clock frequency will not be changed.
Carefullyrecord how many times the led flashes in 30 s. Now enable the divider code line, andrun the program several times, with different values entered for CCLKCFG, initially inthe range 2 to 9. For each record how many times the led flashes in 30 s.
1. Deduce what is the approximate duration of the delay function.
2. Which setting of CCLKCFG most closely matches your original reading?