FIT1047 Study Guide - Final Guide: Sequential Circuits
31 May 2018
School
Department
Course
Professor
Sequential Circuits
Saturday, 26 May 2018
3:49 PM
• Outputs depend on outputs and inputs
• Also depends on sequence of events that have happened in the past
Feedback
• Passing the output back through the input
• Establishes a loop
• Circuit remembers whether input has been set to 1 in the past
Switches
• Controls the memory
Flip Flops
• Memory Component
S/R Latch (Set/reset latch)
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R
S
Q(t)
Q(t+1)
0
0
0
0
0
1
0
1
1
0
0
0
1
1
0
Forbidden
0
0
1
1
0
1
1
1
1
0
1
0
1
1
1
Forbidden
S - Set
R - Reset
Q(t) - Top output at the previous point in time (t)
Q(t+1) - New output at time t+1
• Simple S/R latch can be used to store a single bit of data
• In a CPU, rather than setting and resetting a latch using 2 different signal wires, we want to
store a bit that is represented on one individual wire
• Combine 4 storages cells that an each hold one bit
• This is the D-Flip-Flop
D-Flip-Flop
• Stores a single bit of information
• Reads from the bit from a single input line
• Additional control line (clock) to select whether the stored bit should change or stay the same
• Consists of 3 separate latches
• Output Q. Q' not really needed
find more resources at oneclass.com
find more resources at oneclass.com
