deskthority

Why not both? :p

Regarding the controller to use I really can't help you guys. The bottom line is easy and flawless integration with TMK. The mass storage thing is very nice but not terribly needed imho. Possibly I will develop an online app that will let you download the firmware ready to be flashed, you still need to install a software to flash it of course.

Matt_ wrote: I don't get it. If the controller is meant to be placed here, why should it have a USB port? Would it not be simpler to break out the four USB lines?

two reasons: 1) debug, it is convenient to have a USB port during the dev phase; 2) you can place the controller in other spots if you have a big enough case (eg: directly on the top side and you don't need the extension). Bottom line, we need both options.

So if small PCB is the goal than MKL27Z128VFT4 looks pretty good.

And it may be a good idea to go from 2.54 pitch to 1.27 pitch for the pin headers. Then it will be somewhat good even when people finally realize that big non-split space bars are only a waste of space on the location which is most easily accessible by thumbs.

matt3o wrote: ... 2) you can place the controller in other spots if you have a big enough case (eg: directly on the top side and you don't need the extension).

In such a case the USB socket should be through hole, otherwise it will break off rather quickly.

matt3o wrote: two reasons: 1) debug, it is convenient to have a USB port during the dev phase; 2) you can place the controller in other spots if you have a big enough case (eg: directly on the top side and you don't need the extension). Bottom line, we need both options.

2) is obvious (that's how I initially thought the controller would be used), but 1) also makes sense. Admittedly, as long as it fits, it can't hurt to add a USB connector, the micro variant won't add much height compared to the other components after all.

yeah. usb-c is also an option but I don't know if it requires more components. I'm pretty sure it's more expensive though

Probably, and while it's easy enough to get spare micro-USB connectors to make your own cables, the choice seems much more limited with USB-C (unless the situation evolved quickly since I last checked). Perhaps we can settle on micro for now, and keep USB-C for an hypothetical later revision.

agreed!

matt3o wrote: The mass storage thing is very nice but not terribly needed imho. Possibly I will develop an online app that will let you download the firmware ready to be flashed, you still need to install a software to flash it of course.

Having recently played around a lot with the available bootloaders for the AVR USB chips, I think Mass Storage bootloader (LUFA implementation) is easiest to work with when used in conjunction with an online configuration tool. With the tool, you generate your bin file, yes, bin not hex. Then just put the device in bootloader, which shows up as Mass Storage, and replace the FLASH.BIN file with your new FLASH.BIN file. No drivers or special software is required on the user's machine, just a working internet connection.

Type C connectors are increasingly easy to get, much less expensive than they were a year ago and much more robust than MicroUSB. They're also easy to get in a 'mid-mount' form factor that will make your board thinner. And if you're doing USB 2.0 over Type C, the additional component cost for support circuitry is almost nothing.

mohitgarg wrote: Having recently played around a lot with the available bootloaders for the AVR USB chips, I think Mass Storage bootloader (LUFA implementation) is easiest to work with when used in conjunction with an online configuration tool.

I agree it would be nice to have if possible.

USB 2.0 over type C connectors would be entirely sufficient for most keyboard purposes. I also agree that the connectors are preferable to either mini or micro USB type B connectors: more robust, more compact, much more future proof. Type C will probably still be the dominant standard in 15 years.

I just had a quick look, it seems that they are more widely available indeed. And you can find cheap cables easily as well. So... yeah, why not go with type C after all. It might be a little more expensive, but I don't think an extra dollar or two would be problematic to hobbyists.

I don't think we need usb-c, micro-usb is more than enough, but if cost is not bad and availability good... yeah we can do it

Type-C dimensions are about 9.9 x 9.9 x 3.2 mm.
Micro-USB type-b dimensions are about 7.5 x 5 x 2.9 mm.
Type-C is about 2 times the price of micro-usb, but when all the prices are below $2 then it does not mean much.

So do you want your board bigger to get reversibility when plugging in the cable?
Nothing else will be achieved because the controller is only USB 2.0 full speed; not high speed, not even mentioning super speed.

as I said, micro-usb is good enough for me

I like the Idea of having the possibility of "Addons" on the chip, I'd love to see a platform specific for keyboards. I tried to start my own project but it's a bit confusing for me right now.

A lot of controllers out there and I have no clue where to start.

Anyway, I dig this idea!

I present to you the Nucleus,





Features:
- All 26 I/O lines accessible
- microUSB
- Access to USB data lines
- Small footprint
- 3 3mm mounting holes
- Debug LED

O___________________O

It looks amazing already! What microprocessor is it based on? How do you reset it?

edit: the screw holes look too close to the components though, wouldn't the screw head hit them? Unless they are meant to be screwed from below only

That does look nice!!!!

the usb port is in the wrong spot of course, but you know, nobody's perfect

Yeah, the screw holes are a tight fit I think it might be better to go with 2mm screws, that should give enough room for M2 hex bolts.

It's based on the tried and trusted old dog, Atmega32u4. QFN44 package, passives are 0402, LED 0805. There's a reset switch, forgot to put the silkscreen for it.

Where do you want the micro usb to be placed?

2mm screws would probably be better since you'll want a bit of clearance around the hole so as not to squahs or short any nearby pad/component.

The USB port is meant to be placed on the top edge. That's a very nice proposal, and I like the name too.

looking at mohitgarg's schema I have a feeling we can't put the port on top and keep 18mm height

My gut feeling is that it might fit on the longer side. Will just have to reroute a bit. The basic dimension will remain the same, 18*31 with a 3*10 tab sticking out for the usb.

just one thing... no user names on the board I find it a bit narcissistic

matt3o wrote: just one thing... no user names on the board I find it a bit narcissistic

Uhh how modest matt3o! But I agree, I would not want my sig on anythig either no matter how good it turns out to be. Then users start sending you PM's for support.

matt3o wrote: just one thing... no user names on the board I find it a bit narcissistic

hahaha, as you wish, although I believe there should be some information about the maker.

I'm okay with a URL for reference. but we'll talk about that later...

edit: actually I have http://elf.io available. that would be a wonderful name for this board

matt3o wrote: I'm okay with a URL for reference. but we'll talk about that later...

edit: actually I have http://elf.io available. that would be a wonderful name for this board

That's actually a good name! Now send me a simple image to use as a logo.

URL is fine too.