Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
Ordinarily the choice is based on the application needs. Such question will arise only if there is a critical demanding consideration on resources. If such a situation is there, if tabled, may help one to think along those lines to come up with plasible suggestions.
Regards
Raoof
It is very common to implement a pullup resistor, then attach sinking logic. This would imply active low. You'll also find some logic that is active on one clock phase, while other logic is inactive. By mixing your active signals you can often reduce hardware.
You will find that most digital logic sinks as opposed to sources. Yet in industrial PLC applications you'll find predominately sourcing logic.
It will be usually less resource taxing on the microcontroller doing
a active low output.
Current is pull from outside the IC into the IC.
Active high output, take the supply from the IC.
I always use active low but not for the reasons already given.
Low always means zero volts or close to it. On a system with multiple supply rails, a high could be any one of them and may not be universally recognized, even within a single circuit.
For example, one of my designs uses 5V LCD modules and 2.5V microprocessors. A low is the same for both of them but a high from the microprocessor is still a low as far as the LCD is concerned.
I don't think arguments based on supplying or sinking current are valid. Most ICs have symetrical output stages and their current ratings are roughly the same whichever way it flows.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
