UCR CS 122B
Winter 2004
Prof. Frank Vahid

Homework 3
Due Thursday, 2/19, at the beginning of lecture.

Collaboration encouraged (though each person should turn in unique
solutions) -- 5% extra credit for study groups.

1. (6 points) You are to design a beamformer for an ultrasound machine
   -- the listening to the echo part.  You are to use an off-the-shelf 
   platform chip that contains 50 microprocessors, each with their own 
   memory and timer, and each also accessing one large memory shared by all 
   the processors.  Each microprocessor is connected to exactly 12 
   external chip I/O (pins).  Describe how you might implement a 40 
   (yes 40, not 50) channel beamformer using this platform. 


2. (8 points) 
   (a) Using the web, determine the Joule capacity of a watch battery 
       (pick any one), a AAA battery, a AA battery, and a 9-volt battery. 
       Also determine the active power consumption of a PIC 
       microcontroller, an 8051 microcontroller, and an ARM processor. 
       State the URL sources from which you get each piece of information.
       (I'd like each of you to search the web for this information, so
       while some overlap of sites is O.K. among collaborators, I'd like
       to see evidence of independent search too :-)
   (b) Create a table showing the battery lifetime of each 
       microcontroller/processor using each battery. 
   (c) Assuming a 0-watt sleep mode, determine the percent time that
       each microcontroller/processor can be active if we want the 
       battery to last 1 month, 1 year, or 3 years. 
   (d) Compute APPROXIMATELY the Joules/instruction for each 
       microcontroller/processor. Assume an "instruction" means a
       16-bit instruction. State all assumptions.
       
   
3. (6 points) 
   (a) The target size for SmartDust is 1 cubic millimeter. 
   Draw a figure, to scale, of a 1 cubic millimeter cube.

   (b) Scan the SmartDust web page to determine the basic functionality of
   SmartDust components. Come up with a novel, useful, feasible new 
   application that would be possible using SmartDust components, assuming 
   they are 1 cubic millimeter and cost just pennies each. Your application 
   should not be one of those described on the SmartDust page, nor one of 
   those described in class.