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Adding a USB port to the ThinkPad X1 Nano (the hard way)

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Re: Adding a USB port to the ThinkPad X1 Nano (the hard way)

#31

Post by gzalo »

user_7832 wrote: post #16
gzalo wrote: post #13

I don't get the point of designing and building a 3.3 to 5v booster instead of just wiring a cable to one of the existing USB C vbus 5v pins? Am I missing something?

If I understand right, the existing USB ports are only USB-C. I'm not sure of what implementation the Nano has but if it supports USB-PD it may be able to output up to 20V if the "main" connected device asks for it.

Fair enough, if it supports being charged using any port that is reasonable. I would assume that the notebook has some other internal 5v regulator, maybe for the embedded controller or some other legacy device

Re: Adding a USB port to the ThinkPad X1 Nano (the hard way)

#33

Post by breakingcups »

russdill wrote: post #21
gzalo wrote: post #13

I don't get the point of designing and building a 3.3 to 5v booster instead of just wiring a cable to one of the existing USB C vbus 5v pins? Am I missing something?

It's the safe thing to do. If you source power from some other place you have to worry about not accidentally back powering something by mistake. Granted, this can be accomplished just by carefully ruling out the possibility. Some people would rather just not risk making a mistake here

I'm not an electronics engineer, but is it safe to shift 3.3v to 5v if the underlying hardware wasn't designed for that? Is there a chance to put too much strain on the power source?

Re: Adding a USB port to the ThinkPad X1 Nano (the hard way)

#34

Post by adolph »

Spooky23 wrote: post #24
freedomben wrote: post #2

Amazing adventure and great write up! It reads like an adventure novel :-) > Unfortunately, Lenovo continues to implement a stupid network card whitelist that IBM started over 20 years ago on its ThinkPad models. If the card in the M.2 slot is not advertising a known PCI vendor and product ID in the whitelist contained in the BIOS (now UEFI firmware), the ThinkPad will refuse to boot. Why?? Are there legitimate reaso…

Supply chain integrity comes to mind.

The tao of hardware supply chains. Surely they can do the checksums tho.

https://www.theverge.com/2013/12/29/5253226/nsa-cia-fbi-lapt...

Re: Adding a USB port to the ThinkPad X1 Nano (the hard way)

#36

Post by AshamedCaptain »

5ADBEEF wrote: post #28
AshamedCaptain wrote: post #10

> I use a Logitech mouse which can connect wirelessly to a USB dongle over RF, providing lower latency and better battery life than Bluetooth In my experience this has not been true at all now that most Logitech mice use LE ("Bluetooth Smart") rather than BT. The only advantage the RF dongle has is that it works without an OS.... or on an OS without a BT/LE stack, like here.

RF dongles almost always are Nordic Semiconductor parts and they use their proprietary (but open) protocol called Enhanced Shockburst. The minimum latency of BLE is 7.5ms (fastest connection interval in the spec) while ESB can be in the 100s of microseconds. Not sure about power savings but latency is better.

> RF dongles almost always are Nordic Semiconductor parts and they use their proprietary (but open) protocol called Enhanced Shockburst.

Not really, Logitech actually uses the LE PHY even for their "RF" protocol, at least since the Logitech Bolt controller which is what TFA is talking about. You can sniff Bolt traffic with a LE sniffer.

> The minimum latency of BLE is 7.5ms (fastest connection interval in the spec) while ESB can be in the 100s of microseconds

This makes for an average 4ms of latency, which matches what Logitech advertises. Then USB is then going to introduce 5-10ms at the very least...

Re: Adding a USB port to the ThinkPad X1 Nano (the hard way)

#37

Post by felixg3 »

jwells89 wrote: post #25
AshamedCaptain wrote: post #10

> I use a Logitech mouse which can connect wirelessly to a USB dongle over RF, providing lower latency and better battery life than Bluetooth In my experience this has not been true at all now that most Logitech mice use LE ("Bluetooth Smart") rather than BT. The only advantage the RF dongle has is that it works without an OS.... or on an OS without a BT/LE stack, like here.

Dongles can also be handy for peripherals that are frequently used on different machines, particularly if they don't have built-in multi-pairing and quick host switching. One exception to the "no BT/LE stack" case is the combo of Apple input devices paired with Macs or hackintoshed generic PCs with a handful of Broadcom-based BT chipsets used by Macs. macOS flips some bit on those cards that tells them to keep Apple…

It’s an apple exclusive thing, as they seem to be the only implementer of a USB Bluetooth HID bridge which the Broadcom adapter essentially exposes in firmware. There are a few Bluetooth dongles with CSR chips that can be turned into USB HID interfaces with previously paired Bluetooth peripherals.

Re: Adding a USB port to the ThinkPad X1 Nano (the hard way)

#38

Post by avhon1 »

breakingcups wrote: post #33
russdill wrote: post #21

Earlier quoted context omitted.

It's the safe thing to do. If you source power from some other place you have to worry about not accidentally back powering something by mistake. Granted, this can be accomplished just by carefully ruling out the possibility. Some people would rather just not risk making a mistake here

I'm not an electronics engineer, but is it safe to shift 3.3v to 5v if the underlying hardware wasn't designed for that? Is there a chance to put too much strain on the power source?

The "strain" would depend on how many milliamps your 5V device draws. I don't know the current consumption of these logitech dongles, but it seems to be adequately low for this hack to work.

Re: Adding a USB port to the ThinkPad X1 Nano (the hard way)

#39

Post by Mogzol »

breakingcups wrote: post #33
russdill wrote: post #21

Earlier quoted context omitted.

It's the safe thing to do. If you source power from some other place you have to worry about not accidentally back powering something by mistake. Granted, this can be accomplished just by carefully ruling out the possibility. Some people would rather just not risk making a mistake here

I'm not an electronics engineer, but is it safe to shift 3.3v to 5v if the underlying hardware wasn't designed for that? Is there a chance to put too much strain on the power source?

All that really matters is how much power (watts, i.e. voltage * current) the device draws compared with how much power the laptop was designed to output. Shifting the voltage doesn't really affect anything other than losing some power to conversion inefficiencies.

Re: Adding a USB port to the ThinkPad X1 Nano (the hard way)

#40

Post by AshamedCaptain »

jwells89 wrote: post #25
AshamedCaptain wrote: post #10

> I use a Logitech mouse which can connect wirelessly to a USB dongle over RF, providing lower latency and better battery life than Bluetooth In my experience this has not been true at all now that most Logitech mice use LE ("Bluetooth Smart") rather than BT. The only advantage the RF dongle has is that it works without an OS.... or on an OS without a BT/LE stack, like here.

Dongles can also be handy for peripherals that are frequently used on different machines, particularly if they don't have built-in multi-pairing and quick host switching. One exception to the "no BT/LE stack" case is the combo of Apple input devices paired with Macs or hackintoshed generic PCs with a handful of Broadcom-based BT chipsets used by Macs. macOS flips some bit on those cards that tells them to keep Apple…

It just remembers any peripherals you have already paired with the controller, it's nothing specific to "Apple peripherals". And on the next boot it then shows up as a USB HID device in the pre-OS environment, talking Bluetooth behind the scenes to those same peripherals. I have a (10 year old?) DBT-120 from D-Link which did this, and even Windows had some support for it.

Never seen anything for BLE; my wild guess is that Apple now simply puts a BT stack on their UEFI. Not too far-fetched.

But it doesn't really help the noOS use case, since you still need a BT stack with UI _somewhere_ in order to pair your keyboard for the first time.

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