Author Topic: Alternative controller experiments  (Read 10369 times)

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Offline twiddle

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Re: Alternative controller experiments
« Reply #50 on: Thu, 03 December 2015, 15:09:03 »
Putting the final touches on a prototype BLE PCB.
Will be sending off to the fab sometime soon once I do a few final sanity checks, its the end of the college trimester atm so things are crazy busy.

Offline twiddle

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Re: Alternative controller experiments
« Reply #51 on: Sun, 13 December 2015, 23:19:54 »
Teaser:

Online joey

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Re: Alternative controller experiments
« Reply #52 on: Mon, 14 December 2015, 02:28:32 »
Is U1 the antenna? I haven't looked at BLE/BT at all. Also it says nRF1, but I guess the 1 is here is just the reference. So is it a nRF 51/52?
What about FCC stuff, can you ignore all that for hobbyist stuff?

Offline twiddle

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Re: Alternative controller experiments
« Reply #53 on: Mon, 14 December 2015, 06:20:57 »
Is U1 the antenna? I haven't looked at BLE/BT at all. Also it says nRF1, but I guess the 1 is here is just the reference. So is it a nRF 51/52?
What about FCC stuff, can you ignore all that for hobbyist stuff?

Yep, thats the antenna. Looking at the nRF51 at the moment, just trying to ascertain what options there are for user-flashing of new firmware (theres no bootloader by default). and as far as FCC certification goes, I'm not selling completed items so don't require it.

Online joey

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Re: Alternative controller experiments
« Reply #54 on: Mon, 14 December 2015, 06:33:56 »
Thanks!

No USB either, right?

I should be getting a BBC MicroBit, which has an nrf51 on it, which uses a Kinetis L from Freescale to do the USB parts.

Offline twiddle

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Re: Alternative controller experiments
« Reply #55 on: Mon, 14 December 2015, 06:48:16 »
Yeah. There's a DFU service which allows for over-the-air updates, but I want to do some tests with my development board before I go further with the prototype.

Online joey

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Re: Alternative controller experiments
« Reply #56 on: Mon, 14 December 2015, 08:07:26 »
Hm, I think I'd treat the nRF just as a "module" to send the data, and have the actual matrix driver on another MCU.

Offline twiddle

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Re: Alternative controller experiments
« Reply #57 on: Mon, 14 December 2015, 11:47:41 »
All comes down to cost really. The power circuitry for allowing either USB power or Li-po charging is not cheap, then you add the 'real' MCU on top of the inductors and whatnot needed for the BLE chip.. I'd really rather either use a USB-to-UART interface IC or just leverage over-the-air. Will do as you suggest if all else fails though.

Online joey

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Re: Alternative controller experiments
« Reply #58 on: Mon, 14 December 2015, 13:13:10 »
How are you going to charge the batteries?

I'm not really sure the cost is high enough that it's not worth it!

Offline twiddle

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Re: Alternative controller experiments
« Reply #59 on: Mon, 14 December 2015, 13:41:24 »
Already prototyped a circuit that allows power direct from USB while simultaneously charging the li-po, then disconnecting to use wirelessly.
Uses a charger IC, a power multiplexer, and a buck-boost converter to regulate either output to steady 3.3v.

Offline twiddle

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Re: Alternative controller experiments
« Reply #60 on: Wed, 03 February 2016, 05:54:57 »
I still aten't dead:

Online joey

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Re: Alternative controller experiments
« Reply #61 on: Wed, 03 February 2016, 05:56:31 »
Tell us more!

Offline twiddle

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Re: Alternative controller experiments
« Reply #62 on: Wed, 03 February 2016, 05:59:27 »
Well, not much more to say until the rest of the passives and inductors arrive next week, but I've gone with the dual-mcu option to give the design reprogrammability. When I finish assembly I'll hook those header pins up to one of the PCBs that Ivan was selling that were pre-populated with MX Blacks, but had no controller, and use that to test.

Online joey

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Re: Alternative controller experiments
« Reply #63 on: Wed, 03 February 2016, 06:04:37 »
Is that the nrf51? What's the other chip?

I guess the top left header is JTAG for the main MCU.. how do you program the BT MCU?

Offline twiddle

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Re: Alternative controller experiments
« Reply #64 on: Wed, 03 February 2016, 06:41:05 »
I happen to have a decent number of LPC11u35 parts on hand. The IBDAP firmware turns the LPC into an OpenOCD-compatible CMSIS-DAP debug device capable of programming other things over software SWD.
So, flash my fork of the IBDAP firmware to the LPC using the USB drag and drop bootloader, and you can then debug the nRF chip.
nRF chip listens on UART for keydata and simply transmits it when received, so you shouldn't need to debug it very much, and you can use the 10-pin header to enable debugging the LPC chip which is doing the heavy lifting.
I may set things up so a specific key sequence will make the IBDAP application run, and include it into the binary of the actual KB firmware, but it will come down to flash size.

Online joey

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Re: Alternative controller experiments
« Reply #65 on: Wed, 03 February 2016, 07:11:36 »
I happen to have a decent number of LPC11u35 parts on hand. The IBDAP firmware turns the LPC into an OpenOCD-compatible CMSIS-DAP debug device capable of programming other things over software SWD.
Ah, makes sense!

nRF chip listens on UART for keydata and simply transmits it when received, so you shouldn't need to debug it very much, and you can use the 10-pin header to enable debugging the LPC chip which is doing the heavy lifting.
Sounds good.

I may set things up so a specific key sequence will make the IBDAP application run, and include it into the binary of the actual KB firmware, but it will come down to flash size.

Like you said, it's probably very rare that you need to debug the BT module, so I hope it'd just be an optional thing!

You've made it look pretty easy to make a BT board, will have to pick your brains if I decide to do it!
« Last Edit: Thu, 04 February 2016, 10:17:03 by joey »

Offline iLLucionist

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Re: Alternative controller experiments
« Reply #66 on: Thu, 04 February 2016, 10:07:43 »
This is very cool and detailed. Thought of starting such a project myself. Firmware coding I could do, but now I see this it scares me off a bit.. No experience with circuit design and soldering. Keep up the good work!
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