CPE129_hw9_soln - CPE 129 Homework 9 Solution W Pilkington...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
CPE 129 Homework 9 Solution W. Pilkington 1) The circuit below shows a use of Tri-State Buffers in a configuration called a “Bus Transceiver”. With this arrangement, a device can use the same signal connections to a shared Data Bus to both send and receive information (Input and Output). The “trick” to this arrangement is controlling the “Output Enable” signals for the tri-state buffers properly, so that the device is never trying to input and output at the same time, and is only doing either when it is its turn to use the bus. In a microcomputer system, this is usually handled by the microprocessor supplying a signal that indicates whether the currently-selected device should “Read” or “Write” (the Rd/Wr signal). The selection of which device should Read or Write with the Data Bus is usually determined by decoding the values on another bus, the “Address Bus” (like A 15 & A 14 below). Design the logic circuits needed to generate the “ OutEnable_L ” (active low) and “ I nEnable_L ” (active low) signals controlling the 2 sets of tri-state buffers, so that the “ Input/Output Device ” works as shown in the following Table. Determine the Boolean logic expression for each of 2 circuits. One circuit has OutEnable_L as its output; the other has I nEnable_L as its output. Both circuits may use any of the following 3 signals for inputs: A 15 , A 14 , Rd/Wr’ D3 D2 D1 D0 OutEnable_L InOut_0 InOut_1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/15/2009 for the course CPE 129 taught by Professor Mealy during the Spring '07 term at Cal Poly.

Page1 / 5

CPE129_hw9_soln - CPE 129 Homework 9 Solution W Pilkington...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online