Lectures
1. Introduction to Digital System Design
2. Introduction to the Hardware Description Language VHDL
4. Logic Synthesis
Part1 Part2
5. Programmable Logic Devices - FPGAS
Part1 Part2
6. Arithmetic with FPGAs
Part1 Part2 Part3
8. Clock distribution and synchronization
VHDL Specification of Digital Circuits
The recommended VHDL user guide is the "Vivado Design Suite User Guide for Synthesis (UG901)",
chapter HDL Coding Techniques,
available in http://www.xilinx.com/products/design-tools/vivado.html#documentation
or directly as http://www.xilinx.com/support/documentation/sw_manuals/xilinx2016_2/ug901-vivado-synthesis.pdf
The book "RTL Hardware Design Using VHDL", Pong P. Chu, 2007, includes a significant set of VHDL specification examples. O livro "RTL Hardware Design Using VHDL", Pong P. Chu, 2007, contém um número significativo de exemplos de especificação VHDL de componentes para síntese. Most of these examples are available at http://academic.csuohio.edu/chu_p/rtl/rtl_hardware.html (see code listing).
The book "Synthesis of Arithmetic Circuits: FPGAs, ASICs and Embedded Systems", Deschamps, Bioul e Sutter, 2006, has a set of VHDL specification examples of basic arithmetic circuits in http://www.arithmetic-circuits.org/arithmetic/vhdl_codes.htm
A quick reference guide to VHDL language statements and syntax can be found in Compact Summary of VHDL