How to optimize hblank, vblank, loop ?

r57shell · Post by **r57shell** » Sun Mar 23, 2014 6:49 pm

Are you talking about minimization of logic scheme?
AND, OR, XOR, NAND and other to achieve certain boolean function you need?

Chilly Willy · Post by **Chilly Willy** » Sun Mar 23, 2014 7:44 pm

r57shell wrote:Are you talking about minimization of logic scheme?
AND, OR, XOR, NAND and other to achieve certain boolean function you need?

Yeah; of course, don't forget the "glitch-free" version if you're doing asynchronous SMs. Synchronous State Machines don't have to worry about glitches since they can define the point at which the outputs are sampled. Software State Machines are synchronous by nature due to the program nature of the system. I've seen some data flow processors, which would be analogous to asynchronous SMs, but no normal computer does data flow logic, except as a simulation.

MintyTheCat · Post by **MintyTheCat** » Mon Mar 24, 2014 1:41 pm

Chilly Willy wrote:
MintyTheCat wrote:No, what is meant by the SM Table-Method is a Table of States and their Transitions are Indices into each Table.

Here's a quick Example that I just found here:

http://www.gedan.net/2008/09/08/finite- ... mentation/
Yes, yes, I know... and if you were a hardware engineer, you'd take that table in the example and turn it into boolean equations that generated all outputs without the need for a table or processor doing if/then/switch. Set up a grey code table of the inputs and outputs, circle the factors, and solve the equations. Pretty standard SM problem solving...

this reminds me of University - I haven't done anything like that for ages. I remember making Tables and then simplifying the Logic - God I miss that!

Yes, I am so glad that I never ended up working in GUI Application development.

Chilly Willy · Post by **Chilly Willy** » Mon Mar 24, 2014 5:58 pm

MintyTheCat wrote: this reminds me of University - I haven't done anything like that for ages. I remember making Tables and then simplifying the Logic - God I miss that!

Yes, I am so glad that I never ended up working in GUI Application development.

I've managed to avoid GUI work almost completely in my jobs. I do more for my homebrew than I ever did at work.

I like working on the guts of a program, not the interface. When I needed something for the versions of Doom I did for consoles, I made myself a set of text widgets using about 600 lines of code. It's still the smallest and simplest widget "library" I'm aware of.

Probably the most fun I had at the university was when we made four-bit CPUs in logic class... from scratch! I made a nice microcode controlled design. I wrote a little compiler for the microcode so I could quickly make changes and reburn the EPROMs I used for holding the microcode. It used a two-level pipeline to make things simple and allow for better speed. I even made a state machine in a PAL for the reset logic. I used TTLs for the rest of the logic... a number of folks were using Xilinx chips for their designs. I thought a HUGE board full of TTLs was more fun.

TmEE co.(TM) · Post by **TmEE co.(TM)** » Tue Mar 25, 2014 12:57 am

^ that sounds so awesome !

Chilly Willy · Post by **Chilly Willy** » Tue Mar 25, 2014 8:20 pm

TmEE co.(TM) wrote:^ that sounds so awesome !

It was! And fun! More awesome, but not quite as fun, was when we made out own simple ICs (a few dozen gates or so) using the optical masker and ion injector. Aligning the optical masks was a huge pain.

MintyTheCat · Post by **MintyTheCat** » Wed Mar 26, 2014 12:01 am

When you mentioned 'TTL' I first though of BJTs and not the '74 Series'

Yes, looking back at old electronic Magasines I recall a Microchip PIC comprised solely of 74 Series ICs.

An old Boss of mine told me about how he used to make adders using just Flip-Flops

Some of the early Synth Schematics that I looked at had Op-Amps made of only Transistors - that's a bit extreme