 This week's IonMPI is Nordic, brought to you by DigiKey and AdafruitLadyAida. What is this week's IonMPI? I'm wearing my Nordic shirt. It's very comfortable and I like the style. So I even wear it sometimes when I don't have Nordic on IonMPI. But this week we do. I love to feature Nordic chipsets and I saw this new Dev Kit show up on DigiKey. DigiKey and one of the things I like to do is combine not only NPI, but why I picked it for the NPI and hopefully you learn some stuff. So this week's IonMPI is the Nordic NRF 5340 Audio Dev Kit, which is kind of like this super beefed up NRF 5340 development kit, which is of course audio based, but like hint hint, it's also a really good Dev Kit in general. And at the end we'll show a video that goes through with one of their engineers through like every feature of this Dev Board. But it's a very it's a very classy looking Dev Board. And if you have the PPK and you like that metal glowing plastic section thing they got, this is this has the same thing. OK, so to start off with, you know, when we talked about Bluetooth audio, a lot of people think, you know, if you think about the 90s and early 2000s, the basic, you know, the the killer app for Bluetooth classic was these Bluetooth headsets. You know, they combine a microphone and a headset, sorry, an earphone. You could pair it with your phone very easily by pressing a button and you could use it hands free. It would be great if you're working while you're on the phone. You don't listen to music or you want to chat. More advanced ones eventually added, you know, buttons, user interfaces and even audio commands. They're also Bluetooth classic audio is still used all the time with Bluetooth speakers, even stocks a Bluetooth speaker. I just was like, hey, I wonder if you can get one. Yeah, client tools makes one. It looks pretty well getting cool. And this is very common and low cost. And again, you can pair it with any computer, any mobile device, any tablet, pretty much anything that just Bluetooth audio is going to do. Bluetooth classic audio. And we've been, you know, living with it for like 20 plus years, maybe even 25 plus years, very happily. But, you know, one thing I've noticed is, you know, we've moved from Bluetooth classic to BLE for a lot of devices, like a lot of the gadgets that you have that use Bluetooth, if it's not a keyboard or audio, it's using BLE. And that's because Apple had this restriction on if you wanted to, you know, pair your device with an Apple iOS device for Bluetooth. If it was Bluetooth classic, you had to go through the made for iPod, sorry, iOS or, you know, Bluetooth certification, because everyone was using the SPP protocol. And so it got very complicated to add Bluetooth classic devices, but BLE, you know, you really don't need any permission all in the app, can connect to a custom BLE profile. But again, Bluetooth audio and Bluetooth keyboards have been lagging. Still, most devices that are Bluetooth audio are still classic. And classic audio has one thing, has a couple of things about it that at the time of the design made a lot of sense but are a little restrictive now. One is that classic audio is a single stream that's point to point. You have a thing that sends the audio and you have a thing that receives the audio. And in Bluetooth audio, this is called the source and the sync. This is an example. You can have, you know, a phone that acts as a source. It has audio and it plays into your headset. And then of course, you can also turn the microphone into a stream and then the device is a sync. And you can basically only do one or the other. You can't, you can't do both. Sorry, you can do both, but you can't have multiple devices. And here's, you know, the process in which you, you know, in Bluetooth classic, this is the A2DP protocol specification, which is what a lot of audio devices and Bluetooth classic use and how it kind of negotiates like the codec and the rate and all that good stuff and sets up the communication between the sync and the source. The other choice that was made is the codec. So the codec, the default codec for Bluetooth audio is called SBC for subband codec. It has a pretty good rate of reduction. It goes from 1.5 megabits per second to, you know, a little bit like maybe a quarter of that, 350 kilobits per second. You know, at the time when this was invented, there was limited memory and limited computation. People had to fit the capabilities of encoding and decoding the audio onto the small microcontrollers that would fit into a wireless headset or into the mobile device. And so it wasn't like you could do really advanced codecs compared to what we can do now. Which did create the prolifer, also the quality was, you know, some people would say, hey, the quality wasn't as good as it could be because, again, they were limited. It's like they had a fixed bandwidth on the input and the outputs. They had, kind of, the loss was defined by how much computation you could do to squish down the required 1.5 megabits down to 350 kilobits per second to get over the link reliably. So in the years since, there's been, you know, the proliferation of other codecs. You know, APTX was one of them and AAC is another one of them. And not too surprising is folks who do codec stuff will learn is that they're all very heavily patent and licensed and you have to pay, you know, high licensing fees to use these codecs. So it's like if you want to update or upgrade from SBC to APTX, you have to pay Qualcomm a buck a piece and, you know, a $10,000 starter fee. So, you know, Nordic and Bluetooth.org have a pretty good discussion of like, hey, you know, Bluetooth classic is really popular, but, you know, there's a couple things that, those two things, the fact that it's point-to-point syncing source and the fact that the codec is, you know, the default codec is not really designed for like 20-20 levels of low-power computation. You know, the kind of processors that we now consider low cost enough to stick into a headset would be considered as powerful as a desktop computer back then. And, you know, again, it was really hard to pull people away from Bluetooth Classic. It was cheap. It's easily available. It's, you know, very compatible. Everybody knows about it. Until the killer app came for what would be Bluetooth low-energy audio, which is AirPods. And AirPods. And it's interesting because AirPods don't use the Bluetooth low-energy audio. They actually use their own proprietary protocol. And the reason they need to do this is they have a special problem, which this is LED audio, but the idea is the same here, which is if you have, if you look at all Bluetooth Classic headsets, there's always like, there's a wireless connection, but there's only one wireless codec, and then the two speakers are connected to each other with a wire. Because if you have like one sync, you can't, sorry, if you have one source, you can't have two syncs. I mean, you could, but then they wouldn't be synchronized. Whereas with AirPods and like wireless earbuds, you really need the left and right to be like perfectly in sync. And that's really, really hard for Bluetooth Classic to do. So for like the AirPods, Apple, of course, came up with their own protocol and their own chip and everything because, you know, they, they're Apple and they can afford to do that. But if you want to create something that is basically a multi-stream connection, so you can have two speakers that are independently powered, both getting the same synchronized audio stream, BLE Audio is where it's at. Another thing it can do is broadcast, which could be really useful for like, if you think of like audio tours or like, you know, if you're listening to translations of something in a group and you can set like your headset to just pick up the translation, basically what you would normally use FM radio or like CB radio, you would be able to use Bluetooth or energy. Of course, also these are used for hearing aids as well and there's use cases for that too because, again, now you can have, you know, two hearing aids and they can be synchronized. The other thing is the codec has been greatly improved. It's higher quality and the data rate is lower, which means lower power. You know, the processors that are available for, available now that will use BLE, of course, are more powerful. They can do much more computation and still hit that I2S, you know, time based synchronous audio stream and get the data out. So that's also really important. So there's a new better codec as well. Okay, so you want to, you're like, okay, I'm interested. I want to move from Bluetooth classic to Bluetooth low energy audio. And this is where the NRF 5340 audio dev kit comes in. So each dev kit, what's needed is they're independent, but you can use them as part of like a broadcast or synchronized setup. So you just get as many as you need to kind of simulate the project you need. So if you're doing like broadcast, you'll have one source, and then you'll have multiple of these ADKs as your end devices. So you can, you have a very controlled simulation of, you know, a movie studio, sorry, a movie theater where everybody has their own headsets, for example. And, you know, this dev kit is jam packed. It's got the NRF 5340 in it. It's a dual core ARM Cortex device. And it's got like these Arduino headers, buttons and codec chip and headphone in and line in and line out headphone driver and all that good stuff. Yeah. Oh, hold on. Yeah, I have to do one thing before we go on to the next slide. Okay. This one was so jam packed, Lady Eda. No, I know. Well, I need a break because this is like, this is a pretty long IMPI. Yeah. So we're still here. Okay. So yeah, each dev board you program independently can act as, you know, one earbud or the other. Okay. So this is like a map of the whole thing. I'll say that there's going to play a video which goes through like all of the different options, but I'll say this is also kind of a nice dev kit for the NRF 5340, even if you're not doing audio. There's like the battery monitor and power management and buttons. There's SD card slot. There's Arduino ish headers. There's power monitoring. You can like, you know, easily plug in your PPK or something. If you want to monitor the power or you can even monitor it through, I think in a oscilloscope or a multimeter and there's RGB LEDs as well. And the NRF 5340 is really good for this because it's got a dual core processor. So you have one that just handles like the LE audio controller or like the codec and stuff and then the other one can handle your application or, you know, user interface or whatever else you need to, you know, the LEDs, the buttons or whatever. And so it's good. This is, you know, a handy time to have a dual core processor and you can still take advantage of like the low power modes that Nordic is really good at. I mean, like one thing that, you know, if you want to do low power Bluetooth, you're not going to get anything lower than Nordic. So even though it's a dual core, you'll still be able to cut your power usage quite a bit, which is why many companies, some of which start with a used Nordic chipsets in their devices. And finally, there's a big tutorial that comes with it with software examples. The two big examples are of course the connected isochronous stream where you have two separate syncs, whatever we call syncs, but they synchronize with each other so that they're within a couple of microseconds apart, which is pretty impressive. So they get data and they also kind of communicate with each other a little bit. And then the broadcast where there's one sender and then people can kind of join in to the stream whenever they want to listen in, not necessarily synchronized, but they're all receiving the same data at once. Available on Digikey and you can actually get them. Yes, there's a lot in stock. So again, the reason it's good that there's a lot in stock is because you'll probably want at least two, if not three in order to prototype your project, especially if you're, you know, I want to demo the broadcast example. But the code looks really easy to use. It's all, you know, Python installation. You just use a command line and the Nordic SDK is really well established. And so like, you know, you get the demo running, you can go in and customize the user interface, le is how you want, and then take that and turn it into your final product. All right, we're going to play this video and that'll be IonMPI for this week. This year is the start of this show. Our NF5340 dual core Bluetooth SOC. It supports Bluetooth LE, NFC and many other wireless protocols. What I'd like to highlight for Bluetooth LE audio is the audio PLL and the dual core setup. This enables the SOC's great LE audio performance. The audio PLL supports an adjustable frequency with 3.3 ppm resolution and two frequency bands. It has very low jitter and is ideal for audio applications. The dual core setup enables us to run the application and codec on the application core and handle communication on the network core. This is the Zero's Logic CS47L63, a high performance low power audio DSP for earbud headphones. It is optimized for direct connection to the headphone load. The power management and battery charging are handled by our NPN1100 power management IC. It is a super small, highly efficient PMAC for charging batteries and power delivery. Its power conversion efficiency goes up to 92% with a footprint of only 27 square millimeters. This includes all the passive components. You can even get as small as 23 square millimeters for size constrained applications. At the side of the board we have two 3.5 millimeter jacks to get your sound in and out of the audio decay. One jack is to be used as a headphone connector and the other one for line in, making testing your application as easy as possible. If we look to the right of the board we have buttons for play, pause, volume up, volume down and two user programmable ones. In addition to that we include four user programmable LEDs on the board. The top LED is an RGB LED that can be freely configured. For power measurement we have current measurement pins located here. The different pins enable you to measure the part of the board that you are interested in. Here we have the SWF port for F measurements. If we now look at the back side of the board we see the battery connector. Here you can connect the battery that is included with this kit. This is a USB-C connector and can be used for powering the board or programming and debanging. We've included a digital microphone that is located right here. This is an SD card holder if you need extra memory and here we have RGB LEDs to light up the logo at the middle of the board in the colors of your choice.