# Control Logic

Discussion in 'Homework Help' started by razzler, Feb 9, 2008.

1. ### razzler Thread Starter Member

Feb 9, 2008
16
0
I need help. We were given this block diagram

robot sensors->control logic->counter->memory(btw, from counter to memory, it has a parallel load)

for a line maze robot

is it correct to use a MUX as a control logic?a binary counter as the counter?
and how do we implement stacking/push-pop on the memory?

please help....anyone

2. ### beenthere Retired Moderator

Apr 20, 2004
15,808
295
Elaborate the block diagram for the full process - getting sensor inputs and steering the robot.

You will have two sensors and perhaps only one A to D converter. The MUX will select which of the sensor inputs will be presented to the A to D for conversion.

A counter is a counter.

Each microcomputer has an instruction set. Each instruction set has instructions that PUSH register contents onto the stack, and POP them off.

I'd grab a flowcharting template and start making a decision tree to figure out how to design the line following process.

3. ### razzler Thread Starter Member

Feb 9, 2008
16
0
the robot sensors have outputs of TA(turn around), Left, Right and Forward Movements. I was thinking that from those 4 outputs from the robot sensors, by using MUX, we select the correct movement but since MUX has control inputs, I was assuming that these control inputs(let's say x and y) are power(???). From MUX, the counter counts and PUSHes this to the memory??

I was reading a reference and maybe we could a synchronous binary counter?but I get confused how the output from the counter is used in the memory part

Btw, thanks for your help ^_^

4. ### beenthere Retired Moderator

Apr 20, 2004
15,808
295
You might benefit from some more book time. A multiplexer (MUX) switches several inputs into one output under direction of control inputs. Please note that these inputs are logic and not robot steering controls.

It is possible that there are more than one line following robot designs in existence. Same for the line sensors. We have no idea of the hardware involved in your case.

Nor the electronics. I can state that it sounds like there is a microcontroller involved, or else the term "memory" might not have been used. Also, only computer-like devices have stacks with PUSH and POP instructions.

The counter - synchronous or asynch, binary or decimal - has no obvious utility.

You need to learn more about the devices in your robot, and how to program it to follow lines.

5. ### razzler Thread Starter Member

Feb 9, 2008
16
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the instructor specified that the control logic is the implementation of the backtracking operation to be stored onto the memory.

how do i design a circuit that functions as a backtracker?

6. ### beenthere Retired Moderator

Apr 20, 2004
15,808
295
Then you will need to track the rotation and direction of rotation of each wheel. Every event from the sensors that causes a change will end the count and store the old state, and then the event prompted by the sensor change will have its own file started.

It doesn't sound like you're making much progress with learning about the microprocessor used in this robot. You will have to develop a fair amount of expertise in the care and feeding of this device in order to get the robot project off the ground.

7. ### razzler Thread Starter Member

Feb 9, 2008
16
0
true, we're actually learning about this stuff as we make this circuit and some of the topics like memory and the counters haven't even been discussed yet

8. ### beenthere Retired Moderator

Apr 20, 2004
15,808
295
As I said, counters count. No stretch of the intellect there. But microprocessors have a steeper learning curve. Do some work on your own and get ahead. Of course, the problem with classroom stuff is that there are other courses. When it's your major, you really don't need to have distractions.