[yingste]

Hello,

Does anyone know what battery the dropbear rtc uses? Referring to the coin cell slot under the teensy. I may have missed it but I could not see it either in the wiki or the speeduino store page. Correct me if I am wrong but to my understanding if I insert that and set the time using tunerstudio my logs should have the correct time.

[MadScientistDad]

I think it just needs to be a 3v battery. a CR2032 should work fine. I didn't even realize they had a slot for one lol. The CR2032 is what is referenced from the PJRC page.

[yingste]

I think it just needs to be a 3v battery. a CR2032 should work fine. I didn't even realize they had a slot for one lol. The CR2032 is what is referenced from the PJRC page.

Unfortunately a cr2032 would be too large. The socket isn't that large. Didn't know about the 3v requirement. It looks more like a 377 size but I believe that is 1.5v

[theonewithin]

The Dropbear board takes a CR2032

The Teensy does not require a battery.

[yingste]

Being 20mm across a cr2032 is way too large for the slot. The battery slot is only ~7mm wide and situated underneath the teensy on the dropbear board. I'm aware the teensy does not need the battery but to enable the rtc you would need a battery to keep time when the vehicle is off. Below is a picture of the slot in question with a cr2032 next to it

[pazi88]

Looks like CR12xx holder with quick glance.

[yingste]

Looks like CR12xx holder with quick glance.

Unfortunately even a CR12 would be too large. The slot in total is only ~7mm wide. There is also nothing on the silkscreen nor the holder that would indicate what battery goes in there. If I knew the part number of the holder I could probably look it up but the only marking on it is a polarity indicator.

[pazi88]

Josh answered in Facebook:

I'll be doing a bit more of a write-up on these soon as the SD support develops, but to answer your question it's a ML621 (also goes by MC621). https://www.digikey.com/en/products/det ... ZTN/965124

You will also need to add the centre row header pins on the Teensy board to connect this to the battery

[yingste]

Josh answered in Facebook:

I'll be doing a bit more of a write-up on these soon as the SD support develops, but to answer your question it's a ML621 (also goes by MC621). https://www.digikey.com/en/products/det ... ZTN/965124

You will also need to add the centre row header pins on the Teensy board to connect this to the battery

Awesome. Thanks for finding that. I had forgotten that the facebook page was fairly active.