Electronics is all about the acronyms, there’s no stopping the shortening of ridiculously long names, it kind of runs tangential to our documentation. Sometimes if you don’t know your acronyms it can be like reading a foreign language made up of 3 letter words with minimal vowels. Even after you’ve deciphered what everything is, you’ve then got to work out exactly what the sentence is telling you. We like to be direct and concise us engineers and this often leads to a headache inducing sentence that takes a diagram to understand fully! VHDL is no exception!
VHDL or Very high speed Hardware Description Language, to put it in “layman’s” terms ha, is the programming language predominantly used to program FPGAs (another acronym). It is ultimately one of the most powerful languages of the electronics era, massively useful stuff, it’s right up there in the electronic engineers handbook of languages that the rest of the world doesn’t know exist. My mum still thinks that c programming language is made up of variations between the lower case ‘c’ and upper case ‘c’. She just can’t get why I find it difficult!
VHDL is a language that doesn’t run sequentially, it’s sort of a what ever is occurring at that second kind of language. Imagine you’ve got to go to the shops, if you were sequentially programmed you would go to the shop, select what you needed one after the other, and go pay. When you aren’t sequentially programmed you do many things at once. You would go to the shops and grab everything at once and pay once you had everything. This is because VHDL is programming a logic device in this case a FPGA (Field Programmable Gate Array), it’s not waiting on decisions it’s simply taking the decisions as they arrive and routing them through logic gates to get the desired output. Now for me, this is THE perfect language!
FPGA programming is kinda like drawing out the circuit you want and placing it on a chip in miniature, using VHDL coding. I’m currently using a tool which takes the schematic you draw and converts it into coding. Initially I started learning VHDL coding, but I am working on modifying a previous design which had been written using the schematic tool. I’m hoping I’ll learn lots about logic gates and registers, and get a better grasp of how the language and FPGAs work. After all that’s the hard bit, the syntax will hopefully come naturally after that!
Time to fill my boots with truth tables!