Week 4 - Logic Gates 2 Flashcards
Explain the Arithemic and Logic Unit (ALU)
The ALU is responsable for arithmetic operations (such as addition and subtraction) and logic (such multiplication and division) as well as logic operations such as AND, XOR, NOR and NOT.
Explain DeMorgans Theorim
DeMorgans Theorim describes the equivalence between gates with inverted inputs and gates with inverted outputs.
EXAMPLE: NAND gate is equivalent to a negative-OR gate and a NOR gate is equuivalent to a negative-AND gate.
What is a Latch?
A latch is a logic function that can store a bit/s (or remember its state) until it is reset. An ecample is a SR Latch or D-Flip Flop.
What impact do clocks have in logic circuitry?
A clock can control when a latch can load its inputs after it becomes stable. The importance of this is due to the instability of having to switch inputs to change the output. A clock allows the switch to happen and then when the clock becomes logic high it then allows the latch to read the inputs and make changes. It implements synchronization to the circuit.
What is a register?
A register is simply a location to store bits. The amount of bits to be stores corresponds to the amount of latches needed.
What is a bus? And what are the two types of buses?
A bus is simply a collection of wires used for some common purpose like to convey a set of bits from one component to another.
The two types are point-to-point and multipoint.
How do registers relate to computer memory?
Computer memory is an array of registers in series. Every register has a memory address that is used to select and access the data stored at the register.
Explain brifly the Memory Address Register (MAR) and Memory Buffer Register (MBR)
The MAR is a special register internal to the CPU used to hold the next memory address that will be selected for read/write operations.
The MBR holds the value that was read/written to the selected memory address.
