Hi,
Could someone tell me how to power a Tiny 2040 not using the usb C port? I want to be able to run it from a small Lipo battery but I’m not sure which pins to connect or what the acceptable voltage range is.
Thanks
On the full sized PICO its VSYS. VSYS is the main system input voltage, which can vary in the allowed range 1.8V to 5.5V and is used by the onboard regulator to provide the 3.3V out.
I “think” the pin marked 3V in the pinout is the 3.3v out, not the VSYS pin? I’m not sure what you do for battery on a tiny? You may have to use a powerboost and feed it 5V via the 5V pin.
The Tiny doesn’t have VSYS, but it does have VBUS on pin 1 - the Pico datasheet says that’s tied to the micro-USB power input, so presumably you can feed USB-level power (5v) in there.
(actually looking at the powerchain schematics further down that document, you could probably drive any allowable voltage through VBUS, although obviously you’d have to think carefully about what you were doing if you then actually plugged something into the USB port)
Yeah, VBUS is the one I was referring to. It’s labeled as “5V” on the Tiny itself, and VBUS on the pinout diagram. If it was me I’d use a buck converter etc to boost my LIPO battery to +5V to play it safe. You’d still want to avoid plugging anything into the USB port while the battery is connected though.
Ahh, I was just looking at the pinout rather than the physical item!
It looks like VBUS is just fed into VSYS via a diode, but yeah out of paranoia I’d boost it up too.
If you go with an Adafruit PowerBoost “C” it has a LIPO charger built in. And you can plug power into its Micro USB jack with no issues. Nice stable 5V out. You won’t be able to program the Tiny that way though. It has an enable pin that can be used to turn the Boost section off, which could come in handy. Just ground it and no need to unplug the battery. I have a couple of Pi based builds where I do that and just leave the battery charger running.
“Don’t” use a Pimoroni LIPO SHIM for Pico though. It’s made to match the pinout on the full sized PICO, which doesn’t match the Tiny 2040.
Just thought I’d update this thread.
I had a spare in hand and at £4.32 to replace I thought what the hell I’ll try it.
I wanted to power a tiny 2040 from a 3v cell so I just soldered the leads from a CR2032 battery holder to the pins labelled 5V and - and it worked. I didn’t want to have to mess around boosting the voltage and I need it to be compact so I went with the CR2032 in a holder
The eBay sourced holder has a little switch so you can easily switch the battery off to connect to a USB cable for data transmission.
On a Pico you would use VSYS for battery power. And VBUS for +5V in. I “think” the 3.3V pin on the tiny is the 3.3V out? And the 5V pin is VBUS. Just FYI post.
I’m thinking 3V might be a bit low? 3 AA or AAA on the 5V pin may work better?
But, as I see it, the Tiny 2040 doesn’t have a VSYS Pin?
I have several Pico’s powered by batteries connected to VSYS. I haven’t tries to do the same thing to a Tiny 2040 though?
True; should have said VBUS in the context of a Tiny but they’re sort of the same ;-)
(yes, not quite, but…)
Yeah, you’d likely have to poke around the schematic to see whats what on a Tiny.
tiny2040.sch (shopify.com)