An ALU (arithmetic logic unit) carries out arithmetic and logic operations on operands in computer instructions. It receives an opcode and operands from memory and performs operations like addition, subtraction, AND, OR, XOR. An FPGA (field-programmable gate array) is a programmable integrated circuit that allows a user to implement custom logic functions. Verilog HDL (hardware description language) is used to describe the behavior of digital circuits, including how blocks are connected and data flows through an FPGA.

1. Eembedded
Systems II
ALU and HDL basics

2. ALUs

3. What is an ALU?
 An arithmetic-logic unit is the
part of a CPU that carries out
arithmetic and logic
operations on the operands in
computer instruction words.
 In some processors, the ALU
is divided into two units: an
arithmetic unit (AU) and a
logic unit (LU).

4. How does an ALU
work?
 the ALU has direct input and output
access to the processor controller,
main memory (random access
memory or RAM in a personal
computer) and I/O devices. Inputs
and outputs flow along an electronic
path that is called a bus.
 The input consists of a machine
instruction word, that contains an
"opcode," one or more operands and
sometimes a format code.
 The operation code tells the ALU
what operation to perform and the
operands are used in the operation.

5. Operations supported by ALUs
The following are a few examples of bitwise logical operations and basic arithmetic operations supported by ALUs:
 Addition. Adds A and B with carry-in or carry-out sum at Y.
 Subtraction. Subtracts B from A or vice versa with the difference at Y and carry-in or carry-out.
 Increment. Where A or B is increased by one and Y represents the new value.
 Decrement. Where A or B is decreased by one and Y represents the new value.
 AND. The bitwise logic AND of A and B is represented by Y.
 OR. The bitwise logic OR of A and B is represented by Y.
 Exclusive-OR. The bitwise logic XOR of A and B is represented by Y.
ALU shift functions cause A or B operands to shift, either right or left, with the new operand represented by Y.

6. FPGAs and Verilog

7. What is an FPGA?
 FPGA stands for field-
programmable gate array.
 an FPGA is a hardware circuit
that a user can program to
carry out one or more logical
operations.
 FPGAs are integrated circuits,
or ICs, which are sets of
circuits on a chip—that’s the
“array” part. Those circuits, or
arrays, are groups of
programmable logic gates,
memory, or other elements.

8. Why not MCU or ASIC? always

9. Verilog
 The Verilog Hardware Description Language (Verilog HDL) is a language that
describes the behavior of electronic circuits, most commonly digital circuits.
 Blocking and non-blocking assignments are provided to control the execution
order within an always block. statement execution.
 Port-mapping is the way in which you order your parameters(instantiate your
module). There are 2 techniques:
o Port mapping by order
o Port mapping by name

10. EDA playground
walkthrough

11. Questions?