Hi all,

I just follow an exercise from Embedded design system book (Frank Vahid and Tony Givargis). The problem from exercise 2.13

One controller with two output (S01 and S11) is connected to decoder. Decoder has 4 lamps that will be blink with this sequence (0, 2, 1, 3, 0, 2 ,...).


I try to make a state diagram and table like this attachment.

please any one give me comment whenever it is right or wrong

Best Regard

 

I find marking states with "S0" or "State 0" helps a lot. It also indicates the first state. Also, "I" generally indicates "Input", and "Q" or "O" indicates "Output". I read the state diagram (assuming we begin at State A) as "IF Input SO1 == 0 AND Input S11 == 0, THEN GOTO State B." You may want to show what the outputs of State B are.

Also, I'm having trouble associating the table with your definitions: Q0? Q1?

Try sketching the circuit. Nothing fancy, just a couple of boxes with labeled lines between them.

HTH,
--Rich

 

Hi HTH,

1. S01 and S11 is output, not input. Please see the attachment that is described by this book. I think there is only one input in state register (clk)
2. Q0 and Q1 are input from state register, and I0 and I1 are input to state register
3. I think i don't have problem to drawing circuit if my state table correct

I hope you can give more explanation

regard,

 

(HTH means Hope This Helps! )

You should fill in the decoder's outputs below, then show them in
your state diagram. It would be under the [Sx] in my picture.

Decoder              Decoder
 INPUTS     STATE    OUTPUTS
S01  S11           O1 O2 O3 O4
 0    0       1
 0    1       2
 1    0       3
 1    1       4

                 0,0              1,1        0,0
[Initail State]-------[ S1 ]---//------[S4]-------+
                        ^                         |
                        |                         |
                        +-------------------------+

The S01,S11 outputs from the controller are inputs to the decoder.
The initial state sets up the default values, and waits for the 0,0 inputs.
The values of the inputs change the states. You will need to determine what
the decoder outputs will be for each state. It will probably be

0,1,0,0, 
0,0,0,1
1,0,0,0 
0,0,1,0

but not necessarily.

If this was real-life, I would feed the controller output into a
74xx138 or 74xx139 1 of n decoder, and rearrange the lights so
the proper one would light.

OUTPUT connected to
        LED
  1      1
  2      3
  3      0
  4      2

--Rich