Here are the jumper settings for with Battery or without Battery (Direct DC 5V).
I’m sure this is a silly question but why is there a need for jumpers on both sides? For 4 configs? Is it so we can have battery only, running off of USB while USB charging battery, USB only, and running off of battery while USB is charging battery ?
There are only two configs. The reason we went with jumpers in the first place was to allow high volume user to have the lowest possible BOM cost if they pick one configuration over the other.
The reason there are two jumpers, is they are at two different nets. One bypasses the battery charger, and the other one selects either +3.3V or VBATT to power the modem. The VBATT is quieter (less switching noise) and has more ability to provide and recover from transients. The other reason was to enable a high volume user wanted to switch to 1.8V power for the microcontrollers to use even less current. That way, the design wasn’t anchored to a 3.3V power supply.
We currently don’t support the other two switch configurations.
What we have left is a general user design that can switch between either design, battery + DC, or DC only.
Also, there are no silly questions. This isn’t that kind of forum. We aren’t the angry kind of nerds ;).
So to be clear on the setup for Battery usage.
The battery still get charged by the USB or 5VIN when setup as battery powered?
Correct, the battery is charged when in the battery configuration and 5V DC is connected to 5VIN or via MicroUSB. Once the battery is full, it will stop charging and keep it in charge maintenance.
Does this mean that we will be able to seriously conserve energy? How would that be achieved? Can we use VBATT to power the modem, then use a different power source (1.8V through 5 Vin??) for the chip (or put a switching regulator inline)? I am struggling to understand how to power the modem for high current draw and power the chip for low voltage, specifically 1.8V. I didn’t even know the chip could run at 1.8V. Is this going to be supported by Konekt or does it require customization?
Also, do we know what the other 10 jumpers are on the back of the konekt dash beta? Are these used for testing?
You can already conserve serious energy with the system as-is.
If you were able to switch the microcontroller to 1.8V you would save even more energy. This is not available on the current design, it would require a high volume partnership with Konekt and a board redesign. What we’ve done is make it easier for that to happen. The modem cannot run on 1.8V.
The connectors that you’re referring to are 10-pin ARM programming connectors (JTAG/SWD), not jumpers. Those are going to be removed on the final version. They are just there for debugging the system and to speed up development.
Ah. That’s for JTAG debugging. Makes sense. Thank you.
Consider putting up a blog post about what some of the high volume partners are doing with your hardware or hardware+platform. It would be enlightening.
@DazzlingDuke - the jumpers changed a bit with Dash v1.1. Are the settings still the same - as in jumper close to Ublox chip -> no battery, jumper far from ublox -> with battery? Thanks.
@mfogel - The jumper settings are the same on the 1.1 except for the improved design with only jumpers on one side of the board. No more flipping around each time!
Jumper closer to uBlox chip (No Battery)
Jumper closer to battery and USB connector (Battery)
You’ll also see on the silk screen “NO BATT” and “BATT” in case you want to double-check.
Let me know if that helps clear things up.