Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Software or hardware logic?..... Software logic is easy...
obviously, iwant a hardwere logic using digital ICs.....
hi,
Look at the HEF4585 4bit magnitude comparator.
View attachment 66819
in this ciruit, i'm able to one set of data is greater than or equal.
but i want two sets of data to compare in this automaticaly. it may be 100 and 200. plz frndz help with this.
The easy way is to have two circuits , one for 100 and one for 200.
Connect the 'unknown 8 bits' to both circuit inputs and 100 to one circuit and 200 to the other circuit
Remember you have 4 states, so you need 4 LED's, so you will need some logic on the = > < outputs.
= 100
> 100
= 200
> 200
Then you need to do it with a microprocessor.but i want it in small circuit. not a big one. if i use 4 ICs, then the circuit'll be a big one.
Or you could draw a state-machine with 8-bit input.
If input = 100 it would output A.
For inputs [101 OR 102 OR...OR 199] it would output B
For inputs [200 OR....OR 255] it would output C
For inputs [0 OR....OR 99] it would output D
I have seen this done with an Eprom 27c64 before.... You can program the eprom so that every address above 100 = X then every location over 200 = Y.
This way you will be able to test ANY number.... Just connect your 8 bit data to the address bus... output on the databus..... or use a PLA..
plz elaborate the technique of state-machine. bcz i dnt knw this.
and in that case it'll be and its circuit?
As Ian said, you can use a ROM for that, to implement a truth table.
You can do it with two ICs if you don't need the =100 or =200 outputs.
I have no idea what your application is but if you could be a little more flexible with your values then it's very easy.
>127, >127 < 192, >192 is simple logic gates.
Digital hardware doesn't tend to be decimal friendly.
A PIC 16F5 series, ATMEL or other cheap CPUs will sort this out in a few lines of code as oppose to what could be a few large chips. It's also flexible in that you can change it at a later day without expensive hardware redesign. For simple logic of this kind, the only benefits are flexible power supplies and low current (4000 CMOS). Otherwise such logic is a waste of board space.
Time to move with the flow of engineering. PICs are readily available in India.
I have seen this done with an Eprom 27c64 before.... You can program the eprom so that every address above 100 = X then every location over 200 = Y.
This way you will be able to test ANY number.... Just connect your 8 bit data to the address bus... output on the databus..... or use a PLA..