Thank you so much for describing what AB, A+B, and Ao+B means. For some reason I couldn't find this information online in text form. This helped me tremendously in debugging an ALU I was making in a logic simulator.
This chip was used in legendary computers like Digital Corporation PDP series. Unfortunately production was discontinued many years ago and it’s currently hard to find them now.
@@ducksonplays4190 Guess what?. These chips are most probably recycled from old pcbs. Even at 1 or 2 € a piece, I kind of regard putting them on a hobby project as a sacrilege, like stealing gold pieces of art found in ancient Egypt catacombs just for display on your dining room.
@@ducksonplays4190 Just now they claim they have 120 units left ready to ship. I guess once they are gone they are gone. These chips are definitely no longer in production.
Ah, glad I found your video! I'm building a 6502 CPU clone from TTL chips. I'm just moving on to the ALU now and I'm going to use exactly the chips you used. I'll let you know how I get on.
This is so great. Seven years ago when I was getting into orbital mechanics, I found David's great videos on the Orbiter simulation. Now I am getting into digital electronics, and who do I find again but the amazing David Courtney. Makes me wonder what's next!
Dude, I was trying to understand this truth table yesterday and it kicked my butt. Logical operation duplicated in the arithmetic section. WTF. Now that I understand '+' is 'or' and plus is '+", it totally makes since. :O Wait, What? Thanks for making me less of a dufass. Cheers.
Thankyou for showing this and demonstrating it :) I am going to replicate your design while I work to understand how 74LS181's work so I can use two of these for the ALU in my second 8bit computer I am working on :)
Very interesting video about an interesting IC...thanks. How cool would it be to use this in the Ben Eater computer in place of the adder? I guess it would need some more control signals to set the mode of the ALU, but it would enable a bunch of new instructions. I'm just about to start a build of a computer based on Ben's but probably with more RAM (256 bytes). I figure I'll need one more control signal for that (so a third EEPROM) anyway, and now I'm going to use these also, so thanks for the inspiration!
I think the reason he didnt use these chips is because they are no longer being manufactured so they are relatively hard to find and because u is selling kits it just wouldnt be sustainable
8:22 how this is used when A is allready in A thats silly function. is it atleast plus carry LOL and same on other mode output A so one is with carry and another no carry. silly desing have samethings other mode and function not same LOL thats why its 16 operation not 32. i not find a-b anywhere . i know its a+(bxor+1)
Can you please to show the schematic of this 2 X 74S181 connected in series? Or send to my email; alfredomeurerjunior@gmail.com Did you make the corrections? Thank you very much
is there any chance we can get a schematic of how you connected the two 74ls181s together, I can't seem to get mine to work, and i can't get any help anywhere online, this video is the closest thing to a source that I can find.
@@Kevin192291 When you use the chip in logic mode (M=H) the carry functions do not operate. They only function in Arithmetic mode. Cn+4 of first chip to Cn of second chip for ripple carry. Do not use carry look ahead function. That requires additional special chips. Multiple chips should work quite easily.
Thank you so much for describing what AB, A+B, and Ao+B means. For some reason I couldn't find this information online in text form. This helped me tremendously in debugging an ALU I was making in a logic simulator.
This chip was used in legendary computers like Digital Corporation PDP series. Unfortunately production was discontinued many years ago and it’s currently hard to find them now.
not really www.jameco.com/shop/ProductDisplay?catalogId=10001&langId=-1&storeId=10001&productId=48514 :D and the 74ls181
@@ducksonplays4190 Guess what?. These chips are most probably recycled from old pcbs. Even at 1 or 2 € a piece, I kind of regard putting them on a hobby project as a sacrilege, like stealing gold pieces of art found in ancient Egypt catacombs just for display on your dining room.
@@lsfornells they might be but some chips they stock around 13k a day those about 300 a day
@@ducksonplays4190 Just now they claim they have 120 units left ready to ship. I guess once they are gone they are gone. These chips are definitely no longer in production.
@@lsfornells they have a stock of 300 74ls181s currently
Ah, glad I found your video! I'm building a 6502 CPU clone from TTL chips. I'm just moving on to the ALU now and I'm going to use exactly the chips you used. I'll let you know how I get on.
I'm curious about how your 6502 clone went. Did you get it to work?
This is so great. Seven years ago when I was getting into orbital mechanics, I found David's great videos on the Orbiter simulation. Now I am getting into digital electronics, and who do I find again but the amazing David Courtney. Makes me wonder what's next!
Dude, I was trying to understand this truth table yesterday and it kicked my butt. Logical operation duplicated in the arithmetic section. WTF. Now that I understand '+' is 'or' and plus is '+", it totally makes since. :O Wait, What? Thanks for making me less of a dufass. Cheers.
Your 'little video' was extremely helpful! Thank you very much.
Thankyou for showing this and demonstrating it :) I am going to replicate your design while I work to understand how 74LS181's work so I can use two of these for the ALU in my second 8bit computer I am working on :)
Great video. Thanks really helpful for 8 bit computer
Thanks for the information ☺️
Very interesting video about an interesting IC...thanks. How cool would it be to use this in the Ben Eater computer in place of the adder? I guess it would need some more control signals to set the mode of the ALU, but it would enable a bunch of new instructions. I'm just about to start a build of a computer based on Ben's but probably with more RAM (256 bytes). I figure I'll need one more control signal for that (so a third EEPROM) anyway, and now I'm going to use these also, so thanks for the inspiration!
I think the reason he didnt use these chips is because they are no longer being manufactured so they are relatively hard to find and because u is selling kits it just wouldnt be sustainable
I did that and it worked ou great!
wow thankyou helped alot with understanding the data sheet
Brother we face some problem while performing A plush AB`(B bar)... Please help me.
4:41 you left best thing explained. what happen A=1 B=1 is result 11111101. 1+1=2 and invert. wel logic havet to its sum inverted
active high and active low are different chip, what exactly this is because i connected not gate to output to get result in active high
Great video! what does mean "minus 1" when the S inputs are L L H H?
Wow 😯
I wonder “A+B” and “A PLUS B” is them same?
Okay!! I got that
8:22 how this is used when A is allready in A thats silly function. is it atleast plus carry LOL and same on other mode output A so one is with carry and another no carry. silly desing have samethings other mode and function not same LOL thats why its 16 operation not 32.
i not find a-b anywhere . i know its a+(bxor+1)
how can I combine them ?
It's simple, you feed the carry out of one into the other, and put the same values into function and mode select.
Can you please to show the schematic of this 2 X 74S181 connected in series?
Or send to my email; alfredomeurerjunior@gmail.com
Did you make the corrections?
Thank you very much
👍👍👍👍
is there any chance we can get a schematic of how you connected the two 74ls181s together, I can't seem to get mine to work, and i can't get any help anywhere online, this video is the closest thing to a source that I can find.
Cn+4 goes to Cn on the next alu
Same for me - When I use 1 chip, it works perfectly as expected. When I use two chips, chained, I get very strange results - super frustrating :/
@@SteveYoung359 If you get anywhere, please let me know, It has been over a year and I would absolutely love to revisit this project!
@@Kevin192291 When you use the chip in logic mode (M=H) the carry functions do not operate. They only function in Arithmetic mode. Cn+4 of first chip to Cn of second chip for ripple carry. Do not use carry look ahead function. That requires additional special chips. Multiple chips should work quite easily.
very kewl