The RS-232 protocol

Good to have you back indeed !

Congratulations on your 1 millionth subscriber !

Lol, I literally cancelled on Friday. If you’re back I’m back.

I admire your way of explaining technical topics in ways that doesn't make it sound like you're speaking down to the viewer. A lot of your videos you take the viewer on a discovery journey and it feels clear you're purposedly getting into the hurdles you to illustrate points, making the viewer appreciate a better understanding of what goes on. I tried to explain RS232 to a friend and didn't even come close to this. Great video (as always).

At 24:20, by setting the counter in half_bit_delay to #6 instead of #13, we are not really waiting exactly half a bit though, are we? because the original counter of 13 included the time it took the routine to read the bit, whereas with half_bit_delay, we are waiting before the routine gets executed. Still works, because reading at 1/3 of a bit is fine with a well tuned clock.

I'm currently ill in bed and it's great to have you back making videos.

Great to have you back!!!!!

Glad to have you back, Ben!

Just happy you're alive and well :)

Welcome back! I am excited to check out this new video.

Welcome back, Ben!

Return of the king

Really great to have a new video. Seeing the bits on the scope really helps with understanding how the protocol works and how it copes with lack of clock transmission.

good to have you back

at 22:56 you said 1ghz i think you meant 1 mhz

I sort of knew what 8n1 (or 8e1, etc) meant but not at the bit level. It is great to see a video from you.

YAY!! We missed you and are thrilled to have you back!!

I thoroughly enjoyed that, thanks! Well worth the wait.

So glad you're back!

Welcome Back; glad to see you are ok. Also great video :D

You are back! Great!

I'm so glad you're back!!

Always happy to see a Ben Eater video! Hope to see you expand the 8-Bit BB Computer someday.

Welcome back! Looking forward to watching this!

Great video! Thank you. I think you should name it "The RS-232 protocol" though. Even if it's slightly inaccurate, it will generate more views IMO.

Restored my faith in humanity... all is not lost; thank you for the triumphant return and for affirming that serial is not dead!

Welcome back!!

Odd transition at 9:27

Wonderful to see you back

Happy to see you back, hope you're doing ok!

Welcome back, Ben. I hope you and yours are O.K.

Tiny mistake, at 23:00 you say "1 Gigahertz clock" by mistake instead of "Megahertz". Thank for the video!

I got so much out of the breadboard computer series and I've been patiently waiting for a new video just so I could support you

At first, I thought, that you will use the R65C51 chip, and said to myself, oh I already implemented that on my computer, my jaws dropped when I saw that you are using a single transistor.

What an amazing video to come back with!

Glad to hear from you! Its fun to see you do deep dives into protocols that I use at work. We still use rs-232 in a handfull of locations to interface test equipment on an assembly line.

Yay so glad to see a new post! I found your account a few months ago and I managed to build the 8 bit computer and 6502 computer, working on the graphics card next. But I was very sad to see that you had stopped uploading months before I encountered your channel. Super glad that your back, keep up the great work Ben!

So good to hear from you, Ben! Welcome back. You've definitely been missed.

Wow! I for sure though you had left us all. Very happy (and relieved) to hear from you again.

Great to see you back. I recently discovered your excellent videos, and was somewhat dismayed to see you weren't active online. I'm feeling very inspired by your 8-bit computer and 6502 series, and I remarked to a friend (who has built your 8 bit computer) that it was a shame you didn't seem to be active, and he mentioned this new post, so here I am, a brand new backer :)

Welcome babies, Ben.

Glad to see you back and hope all is well or at least better.

Great to see another video! Some small corrections on the cycle counting: JSR is 6 cycles JMP is 3 conditional branches are 2 if not taken and 3 if taken (plus another one if crossing a page boundary) This probably doesn't change things enough to matter (since it obviously works), because it's still within tolerances when reading 8 bits after the start bit synchronization.

At about 23:03, you said, "... with a 1GHz clock". Pretty sure you meant to say "one megahertz".

FYI, there is an alternate way to get the input bit into the carry flag, if you can wire the input to either bit 7 or bit 0 of PORTA. You do a LDA PORTA followed by a ROL (for bit 7) or ROR (for bit 0). Of course, this modifies the accumulator, so you have some choices: * Push and pull the A register around the LDA PORTA / ROL(R) * Keep the input byte in RAM (you would do ROR $addr to shift in the bit) * If you're not using PORTA for output, you could ROL/ROR PORTA directly to move the input bit into the carry flag, without changing the accumulator. Note that all of these avoid conditional branches, which makes things easier if you're counting cycles for timing purposes.

Hello Ben, Thank you for another great video! Other avenues to explore: Flow control (RTS/CTS, handshakes), differential signals (LVDS) or analog electronics (how to generate a negative voltage from a positive one, charge pumps). Maybe you already had those planned. Best regards, Ed.

Great to see you making videos again!

Welcome back! :)

Really enjoyed it. Looking forward to the next videos and the associated kit.

Woo-hoo! Can't wait to get a chance to sit down and watch this one!

So good. Enjoyed every second of the video. Glad you‘re back!

Holy crap welcome back Ben!

Welcome back. This is great. I like that you're moving to the ability to use a terminal emulator to communicate with it. But how about "just" a keyboard (like an old serial or PS2 style). Some of us may actually have an old one. I'm not suggesting to edit the video -- other than perhaps to mention if it would be at all possible or not (even if not wise) to connect just a keyboard. (And, maybe this is for a later video where you introduce the Serial chips.)

Great video, glad to see you're back!

I wanted so much to add serial to my build! This will surely be super helpful! Welcome back, Ben!

Exciting to see it! I love your deep dives into these protocols that I use often (abstracted through libraries) but never really dove into much.

Beyond elated to see this. It may be unfair of some of us to be concerned but you are a part of our existence now.

Super glad to see you back!

Thanks for the video

And now, all these names and values that I "just knew" make so much more sense! Great intro to serial communications. Minor note: right around 23:02-23:03 you said "...each clock cycle is a micro-second with a one gigahertz clock", when you likely meant "one megahertz clock". Should be fairly obvious you meant "megahertz" since you went over the speed, timing and clock earlier in the video.

Welcome back Ben! We missed you! :)

Yay, making a big batch of popcorn to enjoy this video!

Welcome back :)

So good to see you back!

We were all worried about you. Hope all is well and that you are in good health.

Dude I've been legitimately worried about you! Glad to see you're seemingly good and back at it! Excited to watch the video!

So glad you’re back!

YESSSS, so happy for more of your work

So glad to hear of your return!

Christmas has come early!