Or just to rephrase my question after reading it again, can the VDC_IN to VSYS power supply be of any type,
or does the software (BIOS, UBUNTU, etc.) insist on having communication over the I2C to the BQ25892?
Thank you for interest in the Intel® Joule™ Products.
Yes, powering VSYS (and the corresponding signal that indicates when the module is being powered +VDC_IN) is sufficient to start and run the module, as long as you don’t use a USB power supply. More information here http://www.intel.com/content/dam/support/us/en/documents/joule-products/intel-joule-module-datasheet.pdf, section 3.
Regarding the BQ25892RTWT module that is present in the expansion board (http://www.intel.com/content/dam/support/us/en/documents/joule-products/intel-joule-expansion-board-schematic.pdf, page 25/27); if you want to have a similar setup in your own expansion board, you need I2C communication in order to share data between the host and the BQ25892RTWT (see the simplified schematic of the datasheet http://www.ti.com/lit/ds/symlink/bq25892.pdf).
So, to answer your question, to power up the Joule module, all you need is to provide power to the VSYS port, and if you want to share data between the BQ25892RTWT module and the Joule, you’ll need I2C communication.
I hope you find the previous information useful.
OK, I guess I have to ask differently:
If I don't have any batteries, power my own USB connectors from a different source anyway,
do I need the BQ25892?
Does the current software for the Joule, like the BIOS or Ubuntu expect the BQ25892,
or can it run without?
What problems/limitations to expect, if I don't have a BQ25892 on the board?
The BQ25892RTWT module is a battery charge management system. It is responsible of the charging cycles of Li-Ion and Li-polymer batteries, and it does this without software control. The communication between this component and the Joule is there to help monitor the battery power level (with the help of an ADC).
If you are not planning on using any batteries, you can disregard this component as its absence shouldn’t generate any issues.
Thanks a lot, this was the answer I was waiting for.
I don't have any batteries (OK, I have the one for the RTC), but device will always be powered from the 12V,
never USB or battery. So I can remove this BW2589.
Thanks a lot!
I’m glad we could help you with your question.
If you have any other question, don’t hesitate to contact us through this community.
i'm sure this thread answered this to a degree. I'll let you know my scenario. i don't have a joule or expansion board yet but i'm looking to develop a mobile device using this board. ideally i'd like to power this from a powerbank that is powered by USB. i know that the expansion board says it uses a 12v DC power supply. is powering the module, and sensors possible via USB or should i use a different board. I'm a newbie so if this has been answered or seems ridiculous, please be kind lol.
I’ll suggest you to check the following paragraphs from the Power Source section from the Online Guide for the Intel® Joule™ Module IoT
The development platform can be powered by either a direct DC supply or the USB Type-C connector.
The development platform board requires a 12VDC supply that is capable of delivering a constant 3 Amps of current without a voltage drop.
A USB Type-C power source will allow the board to operate, yet high workloads or attached accessories can exceed the available current on the Type-C bus and cause the board to become unstable or shutdown.
If you have another question, don’t hesitate to contact us.
Have a nice day.