Itsy Bitsy M4 Mis-wired
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Please be positive and constructive with your questions and comments.
- mkurimski
- Posts: 3
- Joined: Thu Sep 17, 2020 2:42 pm
Itsy Bitsy M4 Mis-wired
When wiring up the Itsy Bitsy we accidentally wired both the BAT pin and the vHI pin to a 5V source. The BAT pin is ok to hookup 5V although I am wondering if we caused any damage to the unit supply 5v+ to the vHI pin. The way I understand it is the vHI pin outputs the BAT pin voltage and I don't know if providing 5V to it as "an input" at the same time would cause any issues?
- dastels
- Posts: 15822
- Joined: Tue Oct 20, 2015 3:22 pm
Re: Itsy Bitsy M4 Mis-wired
It shouldn't have causes any problem. There are diodes on Vbus and Vbat to allow sthe higher of the two to provide power to the board. Vhi being at 5v would cause the diode to cut off the 5v from Vbat.
Dave
Dave
- mkurimski
- Posts: 3
- Joined: Thu Sep 17, 2020 2:42 pm
Re: Itsy Bitsy M4 Mis-wired
Just to be clear, we had a jumper from the BAT pin to the vHI pin. I want to confirm that is what you are saying would not cause a problem.
- dastels
- Posts: 15822
- Joined: Tue Oct 20, 2015 3:22 pm
Re: Itsy Bitsy M4 Mis-wired
You are correct.
I was using labels from the schematic. If you are powering externally, connect to the BAT pin. The ItsyBitsy doesn't have a battery charger (unless you add a LiPo backpack) so it's just a way to attach an external power source. It has the benefit of not messing up when you connect to USB to program it... the higher of the two voltaves (BUS/BAT) will be used. Using Vhi as an input will work as long as it's the same or higher than both BUS and BAT, but is more prone to accidental errors: it's meant as an output and there isn't a protective diode on it.
Dave
I was using labels from the schematic. If you are powering externally, connect to the BAT pin. The ItsyBitsy doesn't have a battery charger (unless you add a LiPo backpack) so it's just a way to attach an external power source. It has the benefit of not messing up when you connect to USB to program it... the higher of the two voltaves (BUS/BAT) will be used. Using Vhi as an input will work as long as it's the same or higher than both BUS and BAT, but is more prone to accidental errors: it's meant as an output and there isn't a protective diode on it.
Dave
Please be positive and constructive with your questions and comments.