Counter decoder

This block is functionally similar to the very useful CD4017 integrated circuit. It counts pulses on its Clk pin and displays the result on the outputs. The outputs are decoded so only one output can go high at any one time. For example, if three pulses have been counted then output pin 3 will go high all the rest will be low. Unlike the CD4017, the eChip version can only count to 8 and only has 8 outputs. (This restriction is due to the limited number of pins on the 18 pin PIC)

Set up and run the following system.

Insert a new slide into your presentation and title it 'Counter decoder'.

Put a screen clip of your system onto the slide.

[1]

Carefully explain what the system does.

The CD4017 counter has a reset pin which allows you to reset the counter on any number. For example, to reset when the number 5 is reached you would add this wire:

Livewire clip showing how the reset pin is used on the CD4017 to set the maximum count

You can also reset the eChip counter decoder when a particular number is reached (to give a maximum count). The setting is reached like this:

Change the setting of the counter so that your eChip system could be used for a digital dice where each output represented a different number.

[2]

Explain how the new setting produces the display for a digital dice.

Change your eChip system so that the display continually counts by disconnecting the input and using an appropriate block to produce pulses.

Put a screen clip of the system into your presentation.

Modify your system to produce a complete digital dice. When an input push button is pressed, you need to produce pulses rapidly. These pulses are counted by a counter decoder.

Put a screen clip of the system into you presentation.

[3]

Explain how the system prroduces random numbers.

[4]

Test your dice by rolling it many times. Record your results in an appropriate table and explain how you know the results prove that the numbers are produced randomly.

Extension work