Lecture 11 Flashcards
Given n inputs, how many outputs will a Decoder have?
2^n
What does the input determine in a Decoder?
Which of the outputs gets a value of 1.
Given a computer with 4 memory chips, with 64KB between them and using 16 bits to store an address, how many inputs will need to be given to a Decoder to work out which chip to send the rest of the address?
The first 2. Eg. 00xxxxxxxxxxxxxx - Chip 0 01xxxxxxxxxxxxxx - Chip 1 10xxxxxxxxxxxxxx - Chip 2 11xxxxxxxxxxxxxx - Chip 3
A demultiplexer has how many ‘data’ inputs?
1
Given n ‘control’ inputs, how many total inputs does a demultiplexer have?
n+1
Given n ‘control’ inputs, and 1 data input, how many outputs does a demultiplexer have?
2^n
Given n ‘control’ inputs, how many data inputs does a multiplexer have?
2^n
How many outputs does a multiplexer have?
1
What gates/circuits are in a Full Adder?
Two half adders and an or gate
A 4-bit ripple adder consists of what four circuits?
Three full adders and one half adder
What is gate delay?
The time taken from when an input becomes stable to when an output becomes stable.
What is gate delay also known as?
Propagation delay.
What is the depth of a circuit?
The largest number of gates between any input and any output.
How long does it take for a circuit to settle?
depth * gate delay, assuming gate delay is the same for every gate.
How many gate delays are there in a 4-bit ripple adder?
7
