 Great search bar to you by a different digikey. Thank you digikey. This is when Lady Aida shows you how she uses what I think is the best online component store in the world digikey.com because they stock a lot of a different stuff They talk a lot of stuff in general including the part we're going to talk about tonight Which is always great So the hard part is is how do you find all this stuff and Lady Aida shows you every single week with the great search Lady Aida, what is the great search this week? Okay, this week's great search is where you're gonna learn from my mistakes because I ordered the wrong part and It was fine because digikey has a very generous return policy So it's not a big deal But wouldn't it be great to get the right part when you want to book it and so in this case I was looking for The ESP32 S2 chip for my new cutie pie design. So let's go to the overhead. I'll show my design So this design uses a ESP32 S2 chip and The chip I want is and this is the thing about expressive chips, especially, you know, if you're using the modules and chips They have versions that have built-in flash and RAM But they they look the same because they're it's like just bonded inside the chip And you can't necessarily know unless you buy the right part and another thing is the part marking may not be very clear You you really want to use Express as part selector in the data sheet. Just make sure you're ordering the right thing. So in this case This chip is the we get the right part number when I say it ESP32 No, no, no, you can stay here because I don't know I'll show it. So this is the ESP32 S2 FN4 R2 FN4 means four megabytes of internal flash R2 means two megabytes of PSRAM But the thing is if you look at the chip, which you know, I don't think I'll be able to have it Be too legible, but If you look at the chip marking the R2 doesn't appear, I don't know if you could see it I mean, I can barely see these before putting under camera, but the marking on it is ESP32 S2f and You know, I don't see that. Oh, actually, I do see the N4R To yeah, okay. Sorry. So the the top part says ESP32 S2F and then on the next line below it below it like two lines down it says N4R2 So that's why you would see the the flash and RAM markings However, when I went to order the chip, I ordered the wrong ones and if you Sorry, also as a note if you look at the this module because I actually had to pull apart this module to get the chip You'll see up here. It says ESP32 S2 mini one and then the part that says N4R2 is at the bottom here So it's not necessarily Like the part number is going to be split in two and any of the bonded in flash and RAM are going to be in a separate line Okay, so you've learned that lesson for me. The next lesson is How do you know which one you want to get and so let's go to the computer because I want to show you Yeah, how do you know which one you want to get? Okay, so one thing is is that there's a lot of new expressive chips and that they the information the chip especially when the There is an internally bonded flash and RAM it may not be in the digickey search especially for new chips, so This the S2 FN4 or 2 again 4 megabytes of flash 2 megabytes of PS RAM But if you look down here the memory size shows the non bonded flash and RAM This is the stuff. That's actually on chip which is 120k RAM 320 kilobyte SRM. So that's the memory that's in the chip not on the wire bonded You know system and package Data so what you want to do is I actually recommend going to the expressive website and then under the chip because you know They have so many variations now of every chip and the ESP32 S2 Doesn't have nearly as many variations as the just plain ESP32 which has like a Zillion or they'll have every combo of flash RAM temperature rating But if you go to the product selector You can check the family so in this case I want to check the ESP32 S2 and then This is not yeah, sorry my computer is too low resolution Just really be so down here is all the ESP32 S2 variations and then let's say I Want memory so you can see here. It's like some some chips have No flash and no PS RAM, but let's say I'm like look I want four megabytes of flash and I want you know two megabytes of PS RAM And then when I go down here I Can find that this is The chip that I want to get Which is the Okay, here you go, you can see it so down here you can see for the non-module version of the chip the SOC version It's a mass production the part number is ESP32 S2 fn4 r2 now if I wanted a mini module or like you know We're room module you scroll down on your computer. You'll be able to oh wait school you can see Mini solo we're over. Let's say I didn't want any PS RAM So I turned the PS RAM to zero and then you can see that there's a different version And this is the version I bought by accident the ESP32 S2 fh4 So, you know, there's two versions basically but each one is kind of called ESP32 SF s2 f series You know, I think as long as you're aware of these It's fine. So this is the ESP32 s2 fn4 with flash and PS RAM and if you search for ESP32 s2 fh You'll see that there's the fh2 Two megabytes of flash no PS RAM The fh4 four megabytes of flash also new PS RAM and then The chip I wanted the fn4 r2, which they have in stock, which is actually kind of impressive so if you want to make a design with Built-in Wi-Fi and flash and PS RAM. It's pretty cheap. These are like $1.75 and they're in stock and They're great for you know, just pick in place and the component counts necessary to get this running. It's really minimal You just need a couple passives 40 megahertz crystal, you know antenna and You know good power supply if you could for the folks that are just getting started their engineering career What's a PS RAM? Oh PS RAM is I think pseudo pseudo static RAM It's it's basically you know, you have RAM on chip Usually and that's you know, most of time whatever your mark trollers has built-in RAM like the at mega 328 using the Arduino Uno has 2k The samdi 51 has 192k But if you want massive amount of RAM like two megabytes There's sometimes a peripheral on the chip and this is usually on high-end chips only where you can attach an external SPI flash or Q-Spy flash chip and eight eight pin chip that'll give you slow But large amounts of RAM that the internal chip can address and it thinks that it's like native Very handy for IOT. Is this like back in the day when hard drives would have like a RAM disk? And it's like it's like, oh, we're gonna use your hard drive because we don't have enough RAM It's yeah, it's a little bit like a swap file, but it's not really you're not using flash It is RAM. It's real RAM. It's just it's just RAM. It's SPI It's a way to get to this other storage memory with SPI It's basically if you just want it's because it's handle it look it's address Look at historically you have eight mega eight bit or sixteen bit address to RAM all chips did because there's no internal RAM And this is weird because it's like there's internal RAM and there's external RAM and the PS RAM is just massive and slow and so it's good for It's not good for like you're running variables because in Interrupts for example on the ESP can't use PS RAM you have to use data that's kept on chip but if you are like reading a JSON file from the Internet and you want to parse it and the JSON file is like 400k No chip has 400k of RAM And that's why we like it because circuit Python we're putting all sorts of data on every got images we got Yeah, it's great for it's great for internet stuff because you can just Slurp down the entire XML file and parse it and because the internet's not designed for microcontrollers people just stuff so much data in there Jason and XML files you know it's like something like github you want to get stats for github you have to download Like a massive file it can be like 30k and on a computer. That's not massive. What's funny is like that's not that massive Yeah, what's funny is like 30k is massive for microcontrollers, you know and like for computers when they consider it like well for computers You go to like any web page down when it's like 300 megabytes because all this JavaScript is loaded. Yeah That's like the like the index, you know, yeah, here comes here comes a new framework. So yeah, so that's why I Like the built-in PS RAM and thankfully is now available. So I just picked some up. Okay, and you should too and that's a great search