- Was it possible/suitable to put a shortcut between ItsyBitsy's BAT-port and USB-port ?
- Or does it really need the complex cabling:
external power only to ItsyBitsy's BAT-port and all daughter boards only powered by the ItsyBitsy's USB-pin, not directly powered? (that would make me do much more efforts)
Was this an option: Shortcut between BAT and USB-Pin ?
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- HansH
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Was this an option: Shortcut between BAT and USB-Pin ?
I have connected ItsyBitsy's BAT-Port with the power-In ports of some periferical boards. This works fine for external power but not for USB-powering of the ItsyBitsy, as then all periferical boards remain unpowered, as the USB-pin of the the ItsyBitsy has no power out.
- Franklin97355
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Re: Was this an option: Shortcut between BAT and USB-Pin ?
The bat port is an input pin and not meant to power the other boards. You can power them from the 3V pin if they are 3 volt inputs.
- HansH
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Re: Was this an option: Shortcut between BAT and USB-Pin ?
Yes'I understand that BAT is an Input pin not for output - that's the cause for my question.
I'm looking for a solution, presenting two ideas, I want to have checked by experienced members in the forum :-)
Was it possible or would result in problems, if I short cut the BAT and the USB-pin.
I have no idea, of the internal connections within ItsyBitsy.
I found having the ItsyBitsy connected with an USB cable, this does not state a problem if there is +5V at the BAT port at the same time. Also there is +5V at the USB pin from the USB connection.
So may be a short-cut between USB-pin and BAT-pin might also allow alternative powering with USB and with external power - for ItsyBitsy and all the periferical boards at the same time?
I'm looking for a solution, presenting two ideas, I want to have checked by experienced members in the forum :-)
Was it possible or would result in problems, if I short cut the BAT and the USB-pin.
I have no idea, of the internal connections within ItsyBitsy.
I found having the ItsyBitsy connected with an USB cable, this does not state a problem if there is +5V at the BAT port at the same time. Also there is +5V at the USB pin from the USB connection.
So may be a short-cut between USB-pin and BAT-pin might also allow alternative powering with USB and with external power - for ItsyBitsy and all the periferical boards at the same time?
Last edited by HansH on Fri May 12, 2023 11:10 am, edited 1 time in total.
- adafruit_support_bill
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Re: Was this an option: Shortcut between BAT and USB-Pin ?
The internal connections can be seen in the schematics on the Downloads section of the guide. (This is for the M0 version, but the power section is the same on all Itsy Bitsy boards.
https://learn.adafruit.com/introducing- ... /downloads
Short circuiting the two pins could work - as long as you are extra careful to only have one power source connected at a time. A short circuit would bypass the protection diodes and send 5v USB power directly into your LiPo. Not a good thing!
https://learn.adafruit.com/introducing- ... /downloads
Short circuiting the two pins could work - as long as you are extra careful to only have one power source connected at a time. A short circuit would bypass the protection diodes and send 5v USB power directly into your LiPo. Not a good thing!
- HansH
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Re: Was this an option: Shortcut between BAT and USB-Pin ?
@adafruit_support_bill
Thank You for clarifying.
OK. I found that I can put external 5V to the line, that is, among others, also connected to the BAT pin.
And at the same time I can use the USB-cable for communication with ItsyBitsy. That is has its own 5V-voltage does not seem to interfere with the additional external 5V powering. So short-cutting between the BAT-pin and the USB-pin is not required.
Is this double powering also problematic?
For the next time:
Would it be the intended strategy to put external power only to the ItsyBitsy's BAT-pin and powering all the perifery using 5V from the USB-pin ?
Thank You for clarifying.
OK. I found that I can put external 5V to the line, that is, among others, also connected to the BAT pin.
And at the same time I can use the USB-cable for communication with ItsyBitsy. That is has its own 5V-voltage does not seem to interfere with the additional external 5V powering. So short-cutting between the BAT-pin and the USB-pin is not required.
Is this double powering also problematic?
For the next time:
Would it be the intended strategy to put external power only to the ItsyBitsy's BAT-pin and powering all the perifery using 5V from the USB-pin ?
- adafruit_support_bill
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Re: Was this an option: Shortcut between BAT and USB-Pin ?
You can supply power to both the BAT and USB pins. The Diodes will prevent any conflict between the two supplies. The board will take power from whichever has the higher voltage.
- HansH
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Re: Was this an option: Shortcut between BAT and USB-Pin ?
@adafruit_support_bill
ohhh ... I'm not shure if I understand correctly:
Can the USB-pin also serve as a power-IN pin for the ItsyBitsy, same as the BAT-pin?
Then, what was the reason to have both pins?
Or do You mean the USB-cable to the board?
ohhh ... I'm not shure if I understand correctly:
Can the USB-pin also serve as a power-IN pin for the ItsyBitsy, same as the BAT-pin?
Then, what was the reason to have both pins?
Or do You mean the USB-cable to the board?
- adafruit_support_bill
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Re: Was this an option: Shortcut between BAT and USB-Pin ?
The USB pin is directly connected to the VBUS pin of the USB connector. It is primarily intended to be used as an output for powering other devices.
Because they are directly connected, the USB can also function as an input. However because there is no diode protection between the USB pin and the VBUS pin on the USB jack, you should not connect any USB power source to the USB jack if you are supplying power via the USB pin.
Because they are directly connected, the USB can also function as an input. However because there is no diode protection between the USB pin and the VBUS pin on the USB jack, you should not connect any USB power source to the USB jack if you are supplying power via the USB pin.
- HansH
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Re: Was this an option: Shortcut between BAT and USB-Pin ?
@adafruit_support_bill
OK,
so for the purpose to typically run the whole combination (ItsyBitsy and periferical boards) with external power and only occasionally connect USB-cable for reprogramming, then it might be optimum to
OK,
so for the purpose to typically run the whole combination (ItsyBitsy and periferical boards) with external power and only occasionally connect USB-cable for reprogramming, then it might be optimum to
- have interconnected ItsyBitsy's BAT and all the other power-In ports with external power for regular operation
and to - additionally connect the USB cable, while the board combination remains unchanged externally powered for reprogramming and testing the program.
- adafruit_support_bill
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Re: Was this an option: Shortcut between BAT and USB-Pin ?
Not sure what you mean by "all the other power-In ports".
Electrically, there are only 2 power inputs to the Itsy Bitsy:
* The BAT pin
* The USB jack (which is directly connected to the USB pin)
It might help to post a diagram of how you want to connect things.
Electrically, there are only 2 power inputs to the Itsy Bitsy:
* The BAT pin
* The USB jack (which is directly connected to the USB pin)
It might help to post a diagram of how you want to connect things.
- HansH
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- Joined: Wed Apr 14, 2021 2:49 pm
Re: Was this an option: Shortcut between BAT and USB-Pin ?
@adafruit_support_bill
"all the other power-In-ports" means the power-In ports of all the periferical boards.
"all the other power-In-ports" means the power-In ports of all the periferical boards.
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- adafruit_support_bill
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Re: Was this an option: Shortcut between BAT and USB-Pin ?
That should work fine.
Please be positive and constructive with your questions and comments.