On Wed, Mar 2, 2016 at 10:49 PM, Jakub Kákona kaklik@mlab.cz wrote:
Thanks for the diagram!
no problem.
But I have one more question. Is it really necessarily to operate bq24193's I²C bus at 1.8V?
i don't know! :)
According to datasheet http://www.ti.com/lit/ds/symlink/bq24193.pdf The 1.8V was used only as example of operating voltage.. The Absolute Maximum Ratings for all SDA, SCL and INT pins is 7V and both are "i2c standard open collectors" and could be pulled-up to any rail within the operating voltage range.. Therefore I think the Voltage translator is not necessary...
if you reckon an STM32F072 could handle it, then fine. that saves at least 2 ICs, which is great. if you'd like to actually test it, STM32F072-NUCLEO boards are only $EUR 10 from rs-online, mouser, arrow and digikey.
ok, so key question: what sort of timescale do you think you'd be able to do this in? reason i ask is, i need to work out the timeline.
practical matters: i used eurocircuits to get the PCBs done, they were about 7-10 days (unless you pay extra), and around $EUR 70 for QTY2. i have some components (connectors, switches, capacitors) i can send you.
more practical matters: from mid-april i'm going to be moving to a new country *every month* until the end of the year, to track getting this into a first production run.
l.