 Okay, the great service brought to you by did you key any to prove ladies these are powers of engineering to find stuff on did you key calm lady to what Are you going to show? Okay, so let's go the overhead cuz I'm actually gonna show off just the things I've shown off But again in brief to enter this word segment. Yeah Whoa, whoa so much too much. Okay, so Once upon a time there were computers that had serial ports on them. Can you show the serial port image? Which right and then down to down one this one. Yeah, so once upon a time computers had serial ports and This is a 25 port serial port. Maybe it's a parallel port, but they had 9 pin or 25 pin ports on the back and you could send and receive, you know 8-bit serial data Plus minus 12 volts, but then you know you could convert that to to 0 to 5 or 0 to 3 volts and use that to send and receive data from your electronics and this was amazing and wonderful and we were in the garden of Eden and then You know people took away serial ports and then they were like well We took away your serial port, but it's okay because we're gonna replace it with a USB port and For like about 10 years Microcontrollers did not have USB ports, but they did have serial ports and so we were in this weird murky period Nowadays more chips have built-in USB ports. I'll show one, but if you go to the next image You can use something called a USB to serial converter And this is one of the first circuits I made because it's very handy It takes USB on the left you see a USB B type and on the right you see, you know There's a chip and then a crystal two LEDs and then a couple pads The pads are not labeled because this before you could get so screen on PCBs for free Ground power RXMTX and so the chip in the middle there, which is the FT232BM I believe was a chip that all it did was connect to USB and present a USB port peripheral and convert that to serial and Go back to the computer A lot of microcontrollers now have native USB So actually I'll show I'll just showing this can get it overhead So a board like this Sanity 51 base board It's the Cortex M0 and it has USB and you'll notice there's no chip in between it's just this chip in USB It has a native USB converter Compare that to the UNO which is earlier And so you have the microcontroller and then this little chip here as the USB serial converter And on the Metro Mini We also have two chips Chip USB Converter and and you know the the micro bit actually also basically has a USB to serial converter Although it's USB slash serial slash JTAG whatever but it has a little converter chip and They're not incredibly expensive, but you know, they're they're an added cost But you know if you're dealing with something like a risk 5 chip It doesn't have native USB or some some chips just don't have it and you might be stuck with the chip You have to use or you're upgrading some old design use a USB serial converter. And so I showed the image of the FT 232 BM that one's actually no longer made It was replaced with the FT 232 RL, which I also think is is possibly close to being discontinued So this This I think uses a CP Yeah, this is a CP 2104 And that's another popular side labs also makes USB serial converters Of course The CP 2104 was discontinued as as chips are want to do and it was okay for you know Three or four years because it was like discontinued because they'll get it but now it's really discontinued It was it's been you know, they're no longer making the 04 why I don't you know, maybe there's a little mistake in it Maybe they want to update it So it's been replaced and then for Arduino what they do Which I think is interesting is they use actually a different microcontroller the at mega 30 sorry at mega 16 you too The U stands for USB. It's one of the first USB native chips that At Mel made now you might say well wait a minute if this is and my controller is basically same as this Why not just have one well the Leonardo does it kind of combines both of them But there there are reasons why you might want to have separate We know mostly because there's a ton of code for this chip out there like like tens of thousands of projects maybe a hundred thousand projects and This is just a way of keeping it alive And I think one of the reasons that are do we know did this they what with my controller is to avoid that like oh The parts discontinued or we don't have control over it or or we don't want to customize a little bit Also, it can act as a generic CDC device on your special driver a couple reasons But and I'll say this is always a valid thing to do You can always take a microcontroller and make a converter that said, you know I kind of like for this Incense I do sort of like to use chips that are off the shelf that just kind of do one thing and one thing only I'm always a little nervous when you combine two microcontrollers. I always feel like you can do it But there's always a little bit of risk So let's go to Digi-key, and I'll show you the CP 2104 which is again the chip I Have loved and used and you know, it says that it's available, but it's it's an R&D You know not recommended for new designs and having talked to Silas, you know It's a good idea when this comes up talk to the company and ask them like what do you mean by that because believe me companies have very Wide ranges of what they mean by not recommended it could be I mean I would have the from Sylab is the si I think one one four three You know light sensor and it's been an R&D for like eight years and I can still get it, right? But it's they're like we prefer use a different chip, which they also discontinued anyways So the Sylab ship is not available. Believe me. I have like the last shipments that they're making They're like we're done But they do make others and they'll say that it was trying to search for like USB to UR I wasn't it wasn't as easy to find the category Because it's it's a little it's a little weird location So what I think I found easiest to do is just to click on the function because it's a very specific function and Let's just view all the similar ones. There's a couple some of which are a little bit like it's a bit intense But we just want active ones because we don't want to get stuck again. I think yeah, and So there's a couple options. So I'll say that of the chips There are a few families. So microchip makes MCP to to you know, they have a series of chips Sylab's like I said Cypress Max linear never tried FTDI I have used a lot so my personal opinion is The microchip ones are good But they really are a microcontroller That they are reprogramming to act as a USB to serial converter which is I'm not against but I just haven't haven't used as much The one time I used Cypress It was also microcontroller that they had we basically just reprogrammed and they package it programmed with USB Serial converter code on it and I found it was a little flaky What do I mean by that so? USB serial converters. It's like you'd think it only has one job to do how hard can it be But there's actually a lot of little lot of little details For example, when you open up the serial port what happens to the control lines the DTR and the RTS and the CTS lines and Some plate, you know, some chips like toggle them back and forth Or some of them they don't have like when you try to set the control lines. It doesn't quite work Some of them only support a certain number of bot rates So they only support, you know, 1200 to 115k They don't support the ultra-high bot rates like 3 megabot and you're probably like well When would I read 3 megabot but you will write there's always that once in a while that chip That's like it really wants to be run at 1 megabot or higher and it's really high I need pretty good precision to be able to do Serial at that bot rate. So that's another thing or weird bot rates like 31 to 50 31 to 50 isn't a you know multiplier of 9600 or 2400 But it's used for MIDI and that is also pretty useful too once in a while You need something that takes, you know USB serial and can convert it to a MIDI bot rate Or on the ESP age of 66. I think they use like 77k bot or 77.4 Something something so there's there's times when you'll get these weird These weird ass bot rates or you have to do something with the control lines. And so I will say I've I've tried a lot of Converters and they're not all equivalent. They're not all drop in You definitely want to use it in the weirdest cases that you expect to use it Especially weird bot rates high bot rates And control line, you know noodling Any questions? Yeah, we'll do a question during a great search if that's okay. Um What's the drawback of using a chip as a controller in a converter? Um, you know, it's actually probably okay these days because I think if you use like td usb, it's really solid um There's just um, just make sure again It does control line staff make sure that it does the ball rates you want um You know, some of these are just like, you know, like the silabs and ftdi ones that really rock solid and you know, you use them and I've never had an issue um I just think it's riskier if you use your own chip, although you might be able to save a couple Couple cents, you know, it depends on the quantities you're purchasing. Of course, it's another programming step. You have to take care of It's like another part of your um Production process, which might be annoying. There's also the chance that it gets. Um, it gets erased somehow You know, um chips if if you don't set like your brownouts or if there's a boot loader, it could actually get damaged Um, you know once in a rare rare while, you know, people would get arduinos that we manufacture and they'd say oh The chip has it's coming up as the dfu the 16u2 got erased And we can never figure out why because it would never have made it through the test procedure If it hadn't gotten programmed but something it was really rare again It was like one out of like 10 000 and we just replaced them and we you know We eventually did I think figure out we kind of like added a secondary check or something Um, but it's just it's just another thing that can fail basically Um, so that said, uh, you know the ft series are really good. Um, just look like there's a lot of these in stock One thing that is in stock is the um, again, I haven't tried the mix linear although i'm curious to um, but the cp 2102s I found to be um Very good and reliable. I like these chips, you know, and i'm revising the cp 2104 to use them They're not fully pink compatible with the cp 2104 They're really close, but they do need an extra resistor divider, which I think is what changed I think what what made them switch from the o4 to the o2 is probably Something with the voltage detection, you know, maybe um, there was some risk of damage and so um Yeah, the cp 2102 is maybe a little bit more reliable Right, because it's like these are installed in in so many devices But these um, these are pretty good chips and they come in. Um, I'll say they come in a different couple different flavors This is the 20 pin And they also come in, uh, I think a 28 pin this is the 28 And then I think they come in a 24 and the 24 is like the default is the default maybe I don't remember but look at you look at the data sheet. Yeah, there's the 20 and the 24 and the 28 Um, and the each one is of course a larger package, but it has more like control lines and leds and gpio type things So, um, that said, um, I do like the the silo ones and like the ftdi ones those have been The most reliable for me and the ones that can do the highest baud rates, you know, flawlessly pretty much Okay, that's a great search