 and they were basically sensors that connected over USB. And there's something kind of nice about that, because you want to program something on your computer with like processing or Python, and you want to use your computer, but connect to hardware, and that's like, and Arduino can be, can you do that, but then you have to do this like serial port communication thing. So, some of the boards that we've sold that are really popular are the FT232H and MCP2221 modules, and these are chips that are basically USB to hardware conversion. And you have like a special driver from FTDI, and you know, I don't have an FTDI board here, but basically, you know, you have USB commands in and there's like a couple GPIO, and you can do I squared C and SPI and UART. But the problem is that these chips are like fixed, right? They can only have certain functionality. And what's neat is with the RP2040, you can use this firmware called U2IF. So let's go back to my computer, and I'll show this off, because this is really one of the cool things about Raspberry Pi is this person exec you see Exikyuk, I don't know, whatever. They don't know how to pronounce it. Two years ago, right? They made this firmware called U2IF, and what it does is it takes USB and over HID and turns it into I squared C, SPI, and other capabilities. And what's neat about that is that means that you can on your desktop computer write CPython code that then runs on hardware remotely, like over USB is the transport. And it actually works really, really well. So it's like, you know, they're, they even said, hey, by the way, like you can use Blinka. And we do have this working with Blinka for I squared C, SPI, and PLB women's signal. And you can see they added like more stuff like, you know, NeoPixel stuff that the FT232, like in the MCP221, don't support or I2S. So some of these more advanced protocols are supported. So what that means is, for example, here's my little desktop window, and I'm in my, this says MicroPython, but it's my circuit Python libraries. It's just folder hasn't been renamed. And I'm in the example, sorry, this is, yeah, sorry, I pasted this thing. I'm in this folder where I have all my examples for, my examples for driving the ink display either from a circuit Python board or from a Raspberry Pi computer. But now for my CPython board, I can run what would be like a Blinka with pillow, which is a graphical system in CPython firmware. And I can take advantage of all the power of my computer and I can use it to drive the ink display. So on the overhead, you can flip right back. So this code is running, the code that's drawing these graphics on the ink is running on my computer, sending SPI and GPIO data through U2IF that's running on the RP2040, it's just a firmware blob that I've programmed on here. And it's drawing to the ink display. So what could this be used for? Well, let's say I wanna have an ink display and I wanna have it have a lot of complicated data that needs OAuth, that needs password, that needs computer computation, but how else would you connect an ink display instead of like having some sort of like weird protocol between the RP2040 and like the COM port and it's a transient messages back and forth? I'm just controlling the ink just directly and Blinka transparently thinks of it as like, oh, your computer has SPI and I2C and GPIO hardware. And so this is like one example. So you know, let's say I could have, I could make a little desktop display again connected to my computer, but you can take it a little bit farther than that. Like for example, you could have U2IF running on this RFM feather and now I can connect to sensor nodes and collect the data on my computer, store it to an MySQL library, send it to some online service, interface it with my email or social media, ditto with the Canvas feather. So having a USB to Canvas interface is now like really easy. I run U2IF on this RP2040 and then use SPI and GPIO to communicate with the MCP 2515 SPI Canvas chip. So this definitely like solves a problem that I think, I've seen people have where they're like, I want to have sensor data in or out on my computer, but I need something that can do more than the FT232H. So we will compile the U2F firmware for all these different chip sets. And so that's kind of neat. So some of the things that I'm going through in testing is just, Liz made the firmware file and then I'm just going through and verifying it and then she might do a cool project with this and we can also port some other libraries. Another thing is, I want to show like there's another, and go back to my computer. Dan Halbert who works on circuit path and was like, oh, you know, you're doing these bones boards. Can you make a board that is makes it easy for people to do like prop maker projects because we have the prop maker feather wing and people often plug that into an RP2040 but they're still like soldering required. And basically what Dan was asking is there a solder free way that we can have people make battery powered prop projects that have audio and neopixel and maybe even servos. So this is, this is the RP2040 bones board. And then over here I have a list 3DH accelerometer. So it's like motion and activity. It can detect. This is a five volt level shifter for the neopixel output and this is a Max 98357 I2S amplifier. So the RP2040 doesn't have a DAC but it does have a pretty good I2S support through PIL. So you can have like really in circuit Python it plays audio great and play MP3 files even over I2S. The audio quality is gonna be really good. So we have a class D speaker output and then one button input. So this is gonna be a terminal block. It's not rendering obviously here but it's a screw type terminal block. That's 0.1 inch spacing. And then there's also gonna be a little spot you can plug in a servo. So you can do like pretty advanced projects here. You got like motion, sensing, robotics, neopixels and audio and then one button. So if you wanna have activity. And then if you need more stuff of course you have the full feather pin out. So that's another design. So I finished this one. Sorry, this one got finished this week. And then I'm just kinda designing a couple more RP2040 feathers but I have to finish the ones I've already started. You can see there's like a ton here that I've already begun. So I gotta keep moving on. All right, so I have one more things checking the time. I'm doing good. So the last thing is is that I wanted to make something like the Scorpio, right? But instead of eight eye pins, maybe you would drive like one or two neopixels. But the idea was that it would have your screw terminals, you get a neopixel out and you can get five volts, three amps from USB-C but it is possible to get five amps and five amps would basically be like it's a massive number of pixels. And then you could plug this into a really big USB-C power bank like for a laptop, a power adapter and get five amps out. I probably have to make this a four-layer board just to be able to get that current over to the other side of the board very efficiently. But to do that, I think I need to use a USB type-C power delivery chip. And so I'm starting to develop a breakout board for that that would negotiate the USB power delivery spec. Now, I think that you can do it with just PIO on the RP2040, but some of these chips are so inexpensive, it's like instead of like having to like deal with this protocol, that's like another layer of complexity. The FUSB302 shown here is a chip that connects to the CC pins on your USB type-C. So the CC1, CC2, those are the pins over here. Those are like the extra pins that you normally you would connect a 5K pull-down resistor. But instead of that, they're connected to this chip and this chip can communicate over I-squared-C. And then if you don't send it any commands or requests, I think it just does five volts, one or two amps as usual. But you can communicate with this chip over I-squared-C and say, hey, I want you to negotiate for me and get me a higher voltage like or a higher current or higher voltage or check what current is available. And then the USB-C power adapter communicates back and says, okay, I can give you max three amps. I can give you max two amps. You know, maybe you even want to boost the voltage up to 12 volts for some reason. So this chip does that job. So I want to start with just a breakout for that. And that's what this is. Let's go to common. Let's turn off the back. So this has a USB type-C plug here connected to the F USB 302. The data lines go out here. So if you want to like do, you know, if you want to still get those data lines for connecting to your microcontroller, that's fine. And then it would negotiate Vbus and this Vbus could be anywhere from five to 20 volts. But there's one thing that I had to spec today, which was if you're going to use this chip, it needs three volts for the power and for the chip itself power. And it doesn't have a built-in regulator. So instead you have to get a regulator that will able to handle Vbus going up to 20 volts because normally USB is five volts, but in this case it can go up to 20. And so the great search this week is gonna be, well, this is a little bit cheap. This is one part that's valid. But how to spec a low dropout regulator that can handle 20 plus volts and gives you 2.3 volts out? Yes. So let's do it. All right, ready? Yes. Here we go. Where is the great search brought to you by Digikey and Adafruit. Every single week, ladies and gentlemen, power of engineering and WSU, find the things that you're looking for on digikey.com. Lady, what is the great search of the week this week? Okay. So this week, I'm working on this power delivery chip which would negotiate with a USB wall adapter. And like I have one here, for example. And this wall adapter, you know, it's sorry, this is USB type A. I had a USB type C. Oh, it's over there. Hold on one second, I'll get one. Okay. One second, I'm not going anywhere. Breaking the fourth wall. Yeah, but I mean, it's, I mean, people understand I have legs to get up once in a while. Okay. Yeah, it's not like the Facebook virtual world where the characters have no legs. Okay. So this is a USB adapter with USB C on it. And then let's go to the overhead real fast. And I'll just show the text so people can see it. Okay. So this, I'm going to focus on it. Okay. So you can see here, this has multiple outputs possible. So, you know, there's only one plug, but it can give you five volts, three amps up to 20 volts, three and a half amps. And when you connect normally, if you don't do anything special, it'll give you five volts and be like, hey, you got five volts and this is, be happy with that. But there could be some cases where you have motors or big battery packs or something you want to negotiate and get higher voltages, maybe up to 20 volts. That's the maximum that you can get from USB type C. And to do that, the device on the other, so this is PD, power delivery, the device on the other side has to negotiate. It has to request that higher voltage. And it isn't as simple as just setting a couple resistors. It actually has to like do this like bi-directional communication where it like sends data back and forth to say, hey, what voltage can you supply and how much current and how much do I need and it's what I want. And you know, it's non-trivial, right? So to do that, we're going to use a helper chip. Let's just go to the computer. And the helper chip I'm using right now is the F USB three or two. There's actually a couple of different chips that do this. But this is the one I picked. It's low cost, it communicates over I squared C. It's available on digikey.com for like 60 cents and we'll show that. And what it will do is that this V bus, when you first turn it on, it'll be five volts, but then you can communicate over the CC lines. And this chip is going to say negotiate up to 20 volts. When it goes up to 20 volts, I still need this regulator here that provides 3.3 volts to work. This needs to work no matter what. I don't need a lot of current, maybe only 10, 20 milliamps, but I do want to be able to have it function and not blow up even if it goes up to 20 volts. And I want a little bit ahead of above that too, right? Because you can sometimes get 21 volts out of the USB PD and then maybe there's a little bit of spikiness. And so let's say 24 volts, right? Just to give yourselves a 20% engineering margin. I need to spec a regulator that can give me this. So let's go to digikey. And first off, I'll show you the F USB 302. That's the chip I'm using. Yeah, so this particular one isn't in stock, but yeah, this one is in stock. So there's a whole bunch in the family type C controllers. They're apparently inexpensive. They're like 50, 60 cents, which is a great deal. So you just like plop it on. It's not even very big. Can't do the CC lines. And over I squared C, you have, there's little drivers that are published everywhere from various platforms. Tell it what you want. But like I said, it doesn't have a built-in regulator as far as I can tell. You need to connect an external three volt regulator that can run off of the V USB no matter what. So let's find a 3.3 volts LDO. And so the question is, why am I using LDO, not a buck converter? Mostly because I'm cheap and I don't need a lot of current. A buck converter would totally do a great job here, but it's gonna take up more space. It's gonna cost more because I'm gonna need a diode and I'm gonna need an inductor. I don't need that much current. I'm pretty happy with a very simple LDO that costs maybe 10, 20 cents. It does the job and then I can always redesign this later if I need more current, which would necessitate a buck converter because the power dissipation would be too high, especially if I'm requesting 20 volts or 15 volts. All right, so voltage regulators. And there's a lot. I've already kind of pared it down because I said 3.3 volts, but let's just go to the plain regulator. So if I don't specify 3.3 volts, there's 70,000 regulators. Dude, you gave a lot of stuff in stock. So let's look at active. Let's look at ones that only have a positive output. One regulator and fixed output type. And I also want it to be in stock. So that'll get me down to about 10,000 pieces. Next up, the voltage output I want it to be fixed. You know, if I was willing to go with a adjustable, you know, I set it with a resistor divider, there'd be more options, but frankly, there's a lot of options already. I don't think I need, you know, it turned out I found so many that I was like, you know what? Why have two resistors if I don't need them? So many LDOs have 3.3 volts output. All right, so now I have 1,700 options. Next up, I don't care about the dropout so much because again, I did a lot of current. For current output, I did want at least 100 milliamps. You know, I don't think I'm gonna be able to get seven amps, but you know, I'll go all the way up there just to be complete. I do want to be surface mount, not through a hole. I don't want a TO-22 or whatever. And the voltage input. Now remember, the tough part about this, not the tough part, but the challenge, is that this V bus, which nominally would've been five volts now can be up to 20 volts. And so I need to make sure that my regulator can handle it. So I can't pick anything too low. There is 20, but again, 20 is really cutting it close. You wanna give yourself a little bit of margin. So let's give ourselves up to 24 volts. I don't think 120 is gonna give you anything, but for completeness, I'm gonna select everything above 24. Okay, so now I've got 300 options. Let's look at some of what we got here. So lots and lots of options. This is a very common issue. You know, one of the things that you'll have to decide is the trade-off between packaging and power dissipation. So in general, the bigger the package, the better your power dissipation. You'll have to calculate, if you have 20 volts, if you have 20 volts of output and you are doing 3.3 volts, that's 16 volts difference. And then let's say you're drawing 20 milliamps. So it's a third of a watt. You know, if you're driving, if you're, you know, because the voltage difference times the amount of current, that's how much heat you're dissipating. You know, for this design, I think I'm gonna just warn people, hey, like you're not gonna get, I don't need more than five to 10 milliamps to drive the chip itself. But if you want to use that for other circuitry, you know, you may not, and you've got the 20 volts output, people have to kind of realize that, hey, you know, I'm not gonna be able to get that much current out of it. I think that's fine as long as I document it. I'm going to still stick with going with a Saat 23.5. Although, you know, I think I might do some more math and verify I don't need a Saat 89. Saat 89 is like, it's a little bit bigger, but it has a very good, you see that big tab, it's a nice big heat sinking tab. That said, you know, I think if you see, or you could go with this, a HT Saat 8 with a big power pad on the bottom. So, you know, again, calculate how much current you're gonna need. You need a lot of current. This TO 225 will dissipate like a watt or more. Let's go with the Saat 23 size. So, go over here. And I'm gonna get, I'm gonna skip this Saat 89. Let's do the Saat 23. I'm gonna do the five pin version, which I kind of like, because it doesn't enable pin. And it's also kind of a well-known version, although, well, maybe I'll select these as well. You never know. And then SC 74, that's the smaller version. Well, I'll select also. Okay. So now I've really got not that many options, but you know, if you don't need an enable pin, three pin version will work fine. I tend to like having to enable pin. I don't know why. This is kind of funky. It's like a caterpillar or some sort of eight pin Saat. Don't you see a lot of those? All right. So, a lot of good options. I don't really care about quiescent current. That's something that if you want, you can care about, you know, voltage max again. You know, I don't think I need the higher levels, but let's look at, you know, there's quantity available and pricing. And I kind of like to do a balance between the two. Some really good options here. 36 volt, 24 volts, fairly good dropout. All these have good current capabilities. The RT90 series, GPS 7933, all of them are, you know, good price also, about 50 cents or less. But I was actually kind of into this MCP718 BSN. I'll tell you why. Given that there's like a bazillion options, there was, you know, like 30 options available and more if I was willing to go with a different package. This one, you know, if you have five to nine volts, it will give you 300 milliamps out. So at a lower, you know, as long as you're within the power capabilities of this package, you can get 300 milliamps, which is kind of nice. So if you're having to negotiate, again, maybe you're negotiating only five volts, but you want, you know, five amps, the dropout small enough that this 300 milliamp drive won't, you know, dissipate too much heat. The price was really nice. It was only 25 cents, what a good deal. And then, you know, looking at the datasheet, this used the standard pin out. And there was actually one of the chips that I found there didn't have the standard five pin, sought 23.5 pin out. And it was stable with ceramic capacitors, which is something to watch for sometimes or not. It had thermal shutdown and current limit protection. So again, if people tried to overdrive them, drive it at high voltages, it would be fine. And I've always had really good luck with the on semi voltage regulators, also very low quiescent, which is kind of nice. So all together, you know, a pretty, pretty nice little regulator. So this is my, this is my pick. MCP718, that's what I'm gonna use. That's a great charge. Where is it? Okay, that is our show. Thanks for joining us. Have a fantastic week. That's coming up ahead. We have a ton of stuff and more. We will see everybody later. Thanks everybody. Have a great Easter. That's Descaladiata.