Good morning, all today i'm going to build my version of this, which is a little ch340 usb to serial converter, and i'm going to do it using jlc pcbs, smt assembly service and to make it a challenge, i'm going to use only basic parts now the ch340g Is a basic part? Um! I found a 12 megahertz crystal it's a it's a square one! It's in a little well rectangular package, surface, mount of course uh! That's a basic part can't find a poly fuse in basic parts. I'm not going to bother with it um i'll, be able to find capacitors and resistors. That's no problem. This diode, i'm not sure what it does.

It looks like the um cathode is pointing to positive. So i've got a funny feeling it's um, it's a zener, possibly or just a diode, that's sitting across five volts. No, that wouldn't do anything with it. No, it's got to be a zener.

Yes, it's got to be a zener um. I need a couple of 22 puff load capacitors for the crystal uh 100 n. I think, goes on the 3.3 volts of this. I'm gon na have some leds there's nothing on the back of this board.

Incidentally, oh breakouts, i'm going to break out ground vcc 5 volts not going to bother with the 3.3 volt input, tx rx um. I think it's dtr data terminal, ready and rts ready to send because i believe both of those can be used as reset signals for the pro mini, which will sit here. That's it. This is sitting next to for my usb connector.

I think i'm going to go for the mini b with through hole pins now it appears that you can have smt assembly on uh smd assembly smt. I think they call it. Don't they on a red pcb, so i'm going to go for a red pcb and i'm going to call this one chorizo chorizo using the ch of the ch 340 and the zero on the end. That's what i'm going to call it so here i am in easy.

Eda i've got my ch340g here. I've got my usb connector here, 12 megahertz crystal here and a couple of 22 puff capacitors. So let's go about finding out how i found these items. So if we hit the library um right well i'll start with the 22 puff capacitors, i simply typed in 22pf and there are three basic parts here: we've got no 402.0805.0603, maybe i'll be brave and use an o603 this time.

So perhaps i'll use that part for the ch340, i simply typed ch34 and the basic part is at the top there it's the ch340g. So that's the part i used for my usb connector, i typed usb mini th and it's an extended part this one. It's a mini usb b, 5 pin female through hole c46398, so i'll place it, but i'll when i come to order the board i'll specify that it should not be fitted. It's not a surface mount part anyway and for the 12 megahertz crystal.

I think i simply typed 12 mhz. Let's try that and even without pressing the more button and i'll go to the bottom, to show you that there is a more button there. It is even without clicking that here is um an oscillator surface, mount four pin length and width parameters there, 12 megahertz and it's the yxc one. If i click on it, oh, i think it was uh showing anyway, but there's the uh schematic.

There's the footprint and there's a photograph of the little rectangular crystal. So, let's start wiring it up i'll use the wiring tool to go from d minus on the usb connector to d minus on the ch340 d plus. Oh, that goes straight across and i'm going to use net flags for vcc, so i'll use the 5 volt one we'll put a vcc there, there's another one. There i'll use the ground one there's a ground there ground there on the usb i'll need a ground between my 22 puff capacitors, let's wire those up.

So let's do the crystal now back to the wiring tool. One side of it will go to x in, like so the other side of it will come across here to x, out um we're going to wire that to the 2 22 puff capacitors like so now. These two pads here, four and two, are marked in on the data sheet as ground, so i think i'll ground them uh i'll wire them. Why not? So, let's bring that over to here wire that to ground and similarly to pin two wire that to ground that should work now i need to bring tx and rx out to a connector over here.

Now that's going to have vcc ground, tx, rx, rts and dtr. I believe are the signals i need. So that's going to be a six pin so i'll go to the regular ee library and scroll down to a single row, header i'll go for female, even though i'll probably put male pins in it. The female footprint has smaller holes.

I like it, it's a tighter fit one by six. Oh, i need to click it and place it and that's my output connector. So this connector, let's wire that up, i think i'll - have vcc at the top uh ground at the bottom. But i might put that on.

Pin too i quite like having vcc and ground next to each other, then we'll go for tx and rx and then we'll go for the two control signals which are only used as reset for the arduino pro mini so that it uh installs the program properly. Okay, i'll wire those up and just because it's hard to trace these wires, i'm going to put some net labels on here and i don't really need to bother with five volts and ground because they're close by um. But this one number or pin three on my connector is oh. What was that i kind of remember that's tx i'll put a net label on these four.

I think so. This one is tx t x uh. That means this one has to be rx, but i will check it uh net label. Three is that's dtr, that's i think the one normally used um as a reset, so dt r and the bottom one will be rts rts.

That just helps me remember. What's connected to what so, what remains? Uh v3, the 3.3 volt or possibly three volt input needs a 100 end to ground, so i've got to find a 100 end. Capacitor um! I was just wondering actually, whether i might just go for the ee library and put a basic capacitor in there and then specify it later. Let's do that um.

I prefer this capacitor, the us symbol. So, let's put that in i'll rotate it and put it down here somewhere, uh, that's going to be tricky, but anyway, let's place it there i'll put in the 100 n. Now i just want to see how difficult it is to assign a library component to that. After i've placed it because it's much easier to pick out of this ee lib than go wading through the main library um, we need a capacitor which will be a and i put this symbol for the uh, electrolytic or tantalum.

Probably in this case, are there any tantalums in here yeah tan smd, a eu? Well, let's go for that one and place that up here, uh i'll exit to flip it so that the pos and there go the right way around um. I don't know: let's go for 10 mike there. I don't think it really matters i'll, put an f on there as well and again i'll assign that later um. I think that's probably i might put 100 n next to that as well.

I'll have a think about it. I don't believe, there's anything else. I need i'll just double check. Well, the only other thing.

That's on that little board i showed at the beginning are leds. So, let's put a couple of leds in, i prefer this resistor symbol. The us symbol um: what have we got in there well i'll put in 0 603s? Why not? They can always be changed later so i'll put two in here: i'll need to go a bit higher. Actually, i think, and the leds under here now on that little board, they had the um leds being pulled down by the tx and rx lines and that's probably because they have a better pull down drive than pull up drive.

If i move this five volts up a bit, i can probably link that across to these resistors, like that 1k yeah one case, probably okay, i think that the 102 is on that board. I looked at. Let's get a couple of light emitting diodes led uh. Well, let's have 0603 now shall i worry about red and green.

I suppose i could let's have a red one for this. One rotate that downwards and let's oh, the label is a bit huge there i'll just move that stuff around a bit right. I have pretty sure that that's everything i need now. I just wanted to check this crystal, so i'm going to do a right.

Click um view data sheet that takes me to lcsc.com and it's a yang, zing tech. This thing here, that's a photo of it up. There little surface mount 12 megahertz crystal because i'm just thinking does it have the capacitors built in or do you have to put them in externally? So here's the date sheet? Oh there's not much there just two pages and what does it say, load, capacitance, 10, puff 20 puff or specify. It's not immediately obvious to me here are the the markings ground for pin for ground for pin two one and three are either side of the crystal itself, but does that mean it has load capacitance built in or perhaps you can order it with load capacitance built In i mean it probably won't matter if i put 20 pf, uh or 22pf externally, as well, probably still run, but i just can't work out from this data sheet, whether that the load capacitance is actually built in to this device um.

Some none the wiser really and the other thing i wanted to do was just take a look at this usb connector. So again, i'm going to view the data sheet for that, and that also takes me to lcsc. There's a photograph of it and you can see it's got four mounting pins and five through hole, connector pins, so that's definitely the device. I want i'm going to ask them not to fit it.

I have seen them on ebay, so i'll buy in a few of those and do that component myself. So i think we're ready to go i'll, save my file, otherwise it won't produce a pcb. Let's do a convert schematic to pcb um. There are some unfinished nets now i can't remember who said it, but you can put markers on this little x here.

You can put it on the unfinished nets. What if you can put it directly on those actually like? So, and that should stop it complaining about unfinished nets. There's one there as well uh yeah, let's see if that makes any difference, i'll, save that and do another convert to pcb. Oh, yes, there are now no unfinished nets, handy tool.

Oh no! It's still saying there are some unfinished nets, i'll try and find them uh. Yes, i found the unfinished nets they're on sheet 2 because i left all my other arduino stuff on sheet 2. So i think, actually, i'm just going to delete all of that stuff, because i was hoping that working on one sheet wouldn't bring the other sheet in, but that's not the case so back to sheet one. Do a final save! Oh, it is saved, convert pcb and we got a pcb excellent.

So here's the printed circuit board, uh layout that i'm going to work on now. I want to work in mills, but actually i can see a bigger problem um, which i need to sort out, and that is that capacitors, c8 and c6 are massive, through-hole version. So i need to go back to the schematic and alter those and then update the pcb right. I'm going to work on this printed circuit board, um, probably mostly off camera i'll, go that way around.

I can probably have that sticking over the edge of the board. Just to get roughly everything in position and then i'll um come back and we'll have a look at the selecting of components. Those two components are now c1 and c2, both 100 n. This thing is going to go up here somewhere and there's my crystal and that's going to sit up that end of the ch340, because it connects to these two pins up here.

So i'll get all these other components on my board, get my board sized correctly and then i'll come back and we'll specify components for the capacitors resistors. Oh they're, quite big those resistors. I think they were o603s. Actually i can't remember yes, they are o603 us.

So i'll do that and then i'll come back so an hour or two later and i've got my board. I've called it giuliano chirizzo um. I think i might change that to it so to chorizo v1, because it's highly likely to uh change. Oh that doesn't fit anymore i'll, slightly reduce the text size on that right.

Okay, that's better! So here's my usb mini b through hole, connector ch340! Here now the resistors are o603s and that's because i picked o603 here in my resistor selection - the leds. Well, let's do the capacitors first they're also o603, apart from this one up here, which is a tantalum smd a so i've got to make sure i pick the right one when i specify the components the leds are also o603. I chose a red and a green, but i've got to find those of course, when i pick my components so i'm going to save this now i think. Oh, the other thing i didn't ground the metal work of the usb connector.

I did a quick search for whether you should some people said yeah. Some people said no. Some people said put a resistor capacitor network on it, i'm just going to leave it unconnected. Let's hope it works.

The other thing is: i've put ground planes top and bottom. Various people were saying do that so that you don't etch away unnecessary copper. So that's my top ground plane and there's my bottom ground plane. So i'll just make those invisible.

So we can see everything else. Go back to the top layer so that we can see the silk screen nice and clearly um now. The other thing i might need is some labels on this connector. For because i can see the labels here, five volt ground, tx, rx, dtr and rts.

It probably be better if i had those on the silk screen, so i'll do that now, and so i think i'm ready to um make gerbers. So let's press the g button here and it has incompleted connections. Do you want to check the connections? I think those are just going to be these rats rat lines here for the um usb. Oh, it says usb 3 underscore zero.

So, yes, that's all it is i'm happy to leave that so, let's try g again no keep going and we should go to the place where i can order my board. Oh that looks quite nice. Yes, i've already got my coupon, so i can't do that again. Well, i don't suppose i can so it's a two layer board uh quantity, 5, 1.6 thickness, i'm going to go with red so that it matches my chorizo idea hassle with lead one ounce, copper.

So that's four dollars not including the pcb assembly. Let's click order at jlc, pcb, let's uh check all this. Those are my gerber views. It's two layers: that's the size.

Five boards, single pcb red. I want hassle with led one ounce. No gold fingers don't confirm the production file um fully test. I'm not sure what that means, not sure how they test it.

No cancellated holes don't bother ordering the uh removing the order. Number i'm happy with that down to smt assembly. Now it says, choose the accepted side, so i want parts put on the top. The parts that are not in the jlc pcb smt parts library won't be placed on your board.

Fine and you can't have v cuts with smt assembly, but i'm not doing panelization here. Talling holes added by glc pcb confirm, let's see where that takes me, and that takes me here where i have to add the bom file and the cpl file. So now i think i need to go back to the design and check that my parts are all the correct size to fit on the footprints. So back on my pcb i'm going to click bom and that shows all the parts i've selected now the 200 ends.

Don't have a part number 10 mic tantalum case type. A doesn't have a part number 32 by 16.. This is the oh header. That's not going to be included so i'll.

Take that out later uh, r1 and r2805s. Oh that's interesting! I thought i picked. O603. 10805S.

Are fine and these three i've selected parts for those the mini usb again, i'm going to deselect it for um smt assembly later on now, if you click assign lcsc part number, so this is for the 200 ends. We're just sent straight back to the library. So i can find some items in here and then assign those. Let's give that a try, so that's um, putting in 100 nf has brought me to this.

This is a basic part. 0603. So i think i can select that assign good. That's got an assigned part.

Let's do the tantalum now, i'm not sure how i'm going to find this one. Let's go into capacitors uh tantalum, which is here and see if i can find a case, a 3 32 by 16 and a basic part uh, that's not uh! That might be tantalum. That's ta, if i click it well, i get to see it. Oh yes, that's tantalum.

The little yellow thing there. 10. Microfarads. 106.

uh, it's 3.2 by 1.6. So i assume that's the case. A three two one six. I suppose i could look at the data sheet for that.

Can i do that. Yeah view data sheet, tantalum capacitors, oh yeah, case a three two one. Six that looks like the part i want, so the header i'm not having fitted um. All that's left are the two: oh 805 resistors.

Did i really pick oh 805. I think i might have done. Okay, let's assign a part to that. So they're 1k, let's find a suitable 1k resistor.

So i scrolled down and i hit the more button. A couple of times - and i found this - it's an r0805 1k 1 resistor 1001 - that i think we'll do i'll click that and assign it, and that should be all the parts done everything except the header which i'm not having fitted in any case. So that's all done, that's all the uh bom parts, so i will export the bom that goes into my downloads, folder um. The next thing i need to do i'll close, that is to create the pick and place file.

I don't need to mirror the coordinates so we'll just export that that's easy, and now i can go back to my order page, which was here, i believe and add those two files in so those two files are uploaded. Let's hit next my bom and my pick and place files are in and now i can decide whether i want these items put in or not. Well, i don't want the mini usb put on the board. I don't want the header i do want.

The red led led to green is down there. I think i want everything else. I want the 1k resistors 22 capacitors 10 microfarad tantalum 12 megahertz oscillator crystal. I assume i hope this works ah ch340g and a couple of 100n capacitors awesome.

Next, oh and it's in red, and it should overlay my components. Oh that's! Looking a bit wrong. Uh we've got an orientation problem with u2. Why has that happened? Also, i've got resistors where capacitors go or maybe not.

Maybe it just shows it like that. Well, there's some sort of issue here, i'm going to have to try and solve it. Well, it does say here: the past placement is for reference purposes. Only our engineer will review and fix the components orientation in four to six hours after you place the order you can check the result in your order.

History shall i just rely on that. I think i will, for this i'll rely on them rotating this ch340 and putting it in the right place, so i think i'm going to go for it, which means save to cart so there it is in my cart. The orientation still shows wrong on there, but we hope they're going to fix it so two dollars for the five boards um parts assembly. 19.89.

Of course there are five of these boards. That's a subtotal of 21.89. I'm gon na have to add shipping to that, but i'm gon na go ahead and order that and we'll see what it looks like when it turns up in a box but uh for now cheerio.