Difference between revisions of "CSC270 Homework 9"

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--[[User:Thiebaut|D. Thiebaut]] 19:06, 8 April 2009 (UTC)
 
--[[User:Thiebaut|D. Thiebaut]] 19:06, 8 April 2009 (UTC)
 
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<CENTER>
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<!--CENTER>
 
[[Image:underConstruction.jpg|300px]]
 
[[Image:underConstruction.jpg|300px]]
</CENTER>
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<br>'''UNDER CONSTRUCTION'''
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</CENTER-->
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This assignment is due on Wednesday, April 15th (apparently a day for cake...)
 +
 
 
=Problem #1=
 
=Problem #1=
Give the schematics for a 3-LED sequencer, very similar to what we did before Spring break.  We will label one LED the ''green LED'', another one the ''yellow LED'', and the last one the ''red LED''.
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Design a 3-LED sequencer implemented with a 6811, and draw the full schematics (as we did in Lab 9).  This sequencer behaves very similarly to sequencers you designed with flipflops before Spring break.  We will label one LED the ''green LED'', another one the ''yellow LED'', and the last one the ''red LED''.
  
 
Show the 6811 assembly language program that will activate the LEDs in the following pattern:  Green is ON for 1 second, then Yellow turns on for a second, then Red comes on for a second.  And the cycle starts over with Green coming on.  In other word, create a 3-state sequencer where each LED is ON in one state only.
 
Show the 6811 assembly language program that will activate the LEDs in the following pattern:  Green is ON for 1 second, then Yellow turns on for a second, then Red comes on for a second.  And the cycle starts over with Green coming on.  In other word, create a 3-state sequencer where each LED is ON in one state only.
  
Compare the difficulty/complexity of modifying the state diagram of the sequencer if you were using flip-flops for the sequencer, and the new 6811-based sequencer.  For example, if we decided that Green should stay on for 2 seconds, Yellow for 1 second, and Red for 5 seconds, what are the implications for the  flip-flop based sequencer? For the 6811-based sequencer?
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Assume that we decided that Green should stay on for 2 seconds, Yellow for 1 second, and Red for 5 seconds, comment on the difficulty/complexity of modifying the original sequencer if the sequencer is implemented with flipflops, compared to the difficulty/complexity if the sequencer is implemented with a 6811.
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:::'''Note:''' ''You have two options for this design.  One is to use 3 different outputs (if possible) from the 7442, and connect them to the 3 different flipflops. One is to use the same output from the 7442 and connect it to the 3 different clock inputs of the 3 flipflops. In this case you can use different data bits for the different flipflops...
  
 
=Problem #2=
 
=Problem #2=
  
...In the works...
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Instead of wiring the 7442 as you did in the lab on 4/8/09, when you were implementing the 1-bit Output Port, assume that you had wired the 7442 to the 6811 in the following way:
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* A3 of the 7442 is connected to A13 of the 6811
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* A2 of the 7442 is connected to A14 of the 6811
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* A1 of the 7442 is connected to A15 of the 6811
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* A0 of the 7442 is connected directly to E of the 6811 (no inverter!)
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* Ouput 3 of the 7442 (Pin 4) is connected to the clock input of the 74LS74 flipflop.
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Will this design work?  In other words, will the LSB of Acca get stored in the flipflop when the processor execute
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 +
          STAA 9000
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Why, or why not?  Explain thoroughly why it will or will not work.
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Be careful, this is tricky!  Use all the resources at your disposition to answer this question.
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=Problem #3=
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Assembly by hand the following branches
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<code><pre>
 +
           
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        org    0010
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here:  bra    there
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 +
        org    001F
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there:  beq    where
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 +
 
 +
        org    0080
 +
where:  bne    here
 +
        bra    there 
 +
</pre></code>

Latest revision as of 14:42, 9 April 2009

--D. Thiebaut 19:06, 8 April 2009 (UTC)


This assignment is due on Wednesday, April 15th (apparently a day for cake...)

Problem #1

Design a 3-LED sequencer implemented with a 6811, and draw the full schematics (as we did in Lab 9). This sequencer behaves very similarly to sequencers you designed with flipflops before Spring break. We will label one LED the green LED, another one the yellow LED, and the last one the red LED.

Show the 6811 assembly language program that will activate the LEDs in the following pattern: Green is ON for 1 second, then Yellow turns on for a second, then Red comes on for a second. And the cycle starts over with Green coming on. In other word, create a 3-state sequencer where each LED is ON in one state only.

Assume that we decided that Green should stay on for 2 seconds, Yellow for 1 second, and Red for 5 seconds, comment on the difficulty/complexity of modifying the original sequencer if the sequencer is implemented with flipflops, compared to the difficulty/complexity if the sequencer is implemented with a 6811.

Note: You have two options for this design. One is to use 3 different outputs (if possible) from the 7442, and connect them to the 3 different flipflops. One is to use the same output from the 7442 and connect it to the 3 different clock inputs of the 3 flipflops. In this case you can use different data bits for the different flipflops...

Problem #2

Instead of wiring the 7442 as you did in the lab on 4/8/09, when you were implementing the 1-bit Output Port, assume that you had wired the 7442 to the 6811 in the following way:

  • A3 of the 7442 is connected to A13 of the 6811
  • A2 of the 7442 is connected to A14 of the 6811
  • A1 of the 7442 is connected to A15 of the 6811
  • A0 of the 7442 is connected directly to E of the 6811 (no inverter!)
  • Ouput 3 of the 7442 (Pin 4) is connected to the clock input of the 74LS74 flipflop.

Will this design work? In other words, will the LSB of Acca get stored in the flipflop when the processor execute

         STAA 9000

Why, or why not? Explain thoroughly why it will or will not work.

Be careful, this is tricky! Use all the resources at your disposition to answer this question.

Problem #3

Assembly by hand the following branches

             
        org    0010
here:   bra    there

        org    001F
there:  beq    where


        org    0080
where:  bne    here
        bra    there