Optimal Solution ?

3 messages
Open this post in threaded view
|
Report Content as Inappropriate

Optimal Solution ?

 Greetings, I just finished chapter one and this is the most fun I had in Computer Science since learning Z80 assembler on a trs-80 in the 80's ( pun intended ). Being rather visual in solving the chip designs http://www.cburch.com/logisim/index.htmlis an invaluable tool for building the circuit, testing the logic and easily translate it into HDL code. This was referred to in other posts already , but this is the most actual link. There is not a single solution for each chip, but some require less parts depending on the usage of high or low level building blocks. May I suggest as an additional challenge to add the optimal (minimal) number of  parts for each chip to the Project 1 Chips table so one can verify if the found solution is optimal. Thanks to all involved for this excellent course site.
Open this post in threaded view
|
Report Content as Inappropriate

Re: Optimal Solution ?

 Administrator Optimization is a multidimensional problem, so there is no single "optimal" solution for most of the parts. For example, typical Mux solutions use 4 parts; a mix of And, Or and Not. It's also possible to build the Mux from 4 Nands. Which of those solutions is better? The And/Or/Not solution is much easier to understand, so I would consider it better that the more obscure Nand solution. In the actual physical implementation, neither of these solutions is used. Modern ICs implement multiplexors using transmission gates.     The Not and the transmission gates are 2 transistors each for a total of 6 transistors. A CMOS Nand gate requires 4 transistors. In most physical implmentations, circuit speed, size, and power are a 3-way tradeoff. If you mail me your solutions, I will be happy to comment on them. --Mark