Designing Digital Systems: From Scratch or Reusing Designs?

[mac2cd]

Hi guys I have a bachelor in Electrical Engineering and I have been working in Testing field which is not hard at all ofcourse. I have just been offered a computer hardware engineering position which will involve design development and testing...am not quite sure if I would be able to do it or not so I want to know in the companies, do you mainly just resuse the designs from previous products to build the new one or do you have to make it from scratch...thanks !

 

[jedishrfu]

I think you'd be part of a team that does the design. They would tweak the previous design for performance reasons or port it to a new chip making process or add some new feature. You would be using tools where you might select a shift register from a library of components for that chip technology for your new CPU and the design software would pull in the proper details to add it to the other design layers.

I worked in VLSI testing many years ago and its quite interesting to develop testcases to checkout chip designs. You really get to see how complex the chips are and how its not all like programming a computer and yet it is a computer. Our tests were for VLSI memory testing or engineers handled running simulations on the design and creating test loads for logic chips which were a combination of sequenced test inputs and sequenced expected test outputs. The tester would handle collecting test results and telling what cycles failed whereupon you could backtrack thru the tests and determine what mfg defect caused the failure.

 

[meBigGuy]

I am assuming you are talking digital design.
The larger the team, the less you get to spread your wings. Design tasks vary from High performance uP design where the design engineers know every gate by name, to mixed signal embedded systems where you need to be able to take a system level view, and design/integrate multiple components and controllers. In the latter case you commonly develop new sub-systems that get used over in subsequent designs and need to be able to integrate externally developed IP.

The best design engineers are the ones that can write the best testbenches. Your experience there will be very helpful.

I've always avoided the "timing specs from the timing group, power specs from the power group, functional specs from the systems group, toss it over the wall to the test group, toss it over the next wall to the backend group" environment that occurs on a large team digital project. But, that's me.