Tri State Buffers and Registers
Circuit #1 - Register
A Register gives us the ability to store an 8bit number and is the basis of computer memory. Only when the clock is triggered (in this case Rising Edge) does the input get stored.
Circuit #2 - Register (hex i/o)
This simulation is the same as the previous circuit except the input and output are being represented by HEX digits instead of binary. You can zoom in on section of the drawing by right clicking on the drawing and selecting zoom.
Circuit #3 - Tri State Buffer
Tri State Buffer Truth Table
Note: A bubble really should be shown on tri state buffer for the Output Enable Pin (OE), but has been left off this diagram. Typicall OE pins are ACTIVE LOW.
The buffer is an inverting buffer, hence the input is inverted when the output is enabled.
High Z is just like an open switch disconnecting the output side of the gate from any circuit connected to its output.
Circuit #4 - Multiple Registers to a Common Output via Tri State Buffers
This is an example of two registers using a common input and output (the output via tri state buffers). Place a value in the hex input blocks and store it to either the Top or Botton Register (using one of the CLK inputs). Then place a second value in the second register. Then using the OE inputs on the bottom of the simulation, output the values one at a time to see the results.
Again, you can right click on the simulation to call up a menu and then use zoom to get a blow up of part of the simulation.