Switches to CPUs: Relay based latches
ฝัง
- เผยแพร่เมื่อ 7 ก.ย. 2024
- We look at implementing a latch with relays.
Part 1: Binary numbers - • Digital Logic Explained
Part 2: 2-input gates - • Switches to CPUs: 2 In...
Part 3: Relay based logic - • Switches to CPUs: Rela...
Part 4: Latches - • Switches to CPUs: Rela...
Part 5: SR Latch - • Switches to CPUs: Set ...
Part 6: Wired OR gates - • Switches to CPUs: Wire...
Part 7: Flip Flops - • Switches to CPUs: Flip...
A relay based latch :) makes me smile
Outstanding video. Looking forward to the next video!
Thanks for the feedback!
Mention relays and I'm there. Talk about click bait.
Ha ha. More click than bait though I think.
@@DrMattRegan LOL
Groan, take my up vote.
Minor correction: the Atari 2600 used the MOS 6507, which was a cut-down version of the 6502.
True. I’m thinking to keep it simple. C64 also used the 6510, but they are based on the 6502 architecture.
All of the masks of the 6507 were the same as the 6502 except for the metallisation layer that was slightly patched to disable interrupts (the 6501 was also the same chip with a different patch to the metal layer to bypass the internal clock generator). The main difference was the smaller 28 pin package to reduce cost. All the transistors and pin pads of the 6502 were there in the 6507.
Yeah, from my understanding the upper couple of address lines weren't visible from the outside.
No errors that I could see here, either.
As alluded to in one of the other comments on the video, you can make a single-relay latch by hooking the ON output from a relay up to it's own coil. (Basically a buffer with its output connected to its input.) I can see why you did it the way you did in the video, though, since the two-relay latch demonstrates the concepts involved (especially when things end up translated to transistors) a bit better. (I think the differences between how relays and transistors work mean that the single-relay version loses its advantages when translated to transistors, too, but I'm not 100% sure on that.)
Thanks. I'm trying to introduce one idea at a time, so i want to keep the relay implementation close to the gate version.
In the 6502 itself, it has about 13 8-bit registers (including hidden registers), so switching to a single relay per bit saves
a huge number of relays.
You win. I just ordered 30 relays and signal diodes. They're five volts, so I can interface them with digital electronics. The covers are opaque so not as cool as yours.
Cool, have a look at Dieter Muller's relay based ALU, that's what i'm planning to use down the track.
@@DrMattRegan Thanks for the pointer! I found it and that design is incredibly economical. The control signals are a hit of a PITA though, but the ALU chips I have seen are similar.
@@mheermance yeah, I think the 181 does something similar
Cliff hanger? 🙂
Yes, well I’ll get the next part up soon. I showed this to my teenage kids and they wigged out at this point. I’ll include Set Reset in the next one.
The latch can be done with one relay only, am I right?
Correct 👍. Will be going there a bit further down the track when I start to build registers.