charging bl-5c | bl-6c
andy at openmoko.com
Fri Feb 15 23:12:55 CET 2008
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Somebody in the thread at some point said:
>>> What does our original battery, i.e. the one without the coulomb
>>> counter, speak on that middle pin?
>> Nothing, it's a dumb temperature sensor.
> So it would certainly fail to respond to any HDQ conversation (er ice
> breaker if you'll pardon the horrible pun).
Yes it'll give ERROR -62 (-ETIME) or 0x00 for everything (Hm I didn't
think about checking for the shared pin forced to 0V all the time, it
can be added if it is a real consideration).
>> What led us to understand these kinds of battery aren't getting charged?
> I wonder if we had it backwards: Putting our battery in a phone that is
> designed for a BL-6C might result in our battery not being charged. In
> fact, the phone might refuse to switch on. My Nokia which uses a 5C says
> something like "battery error" and refuses to power up if I insert our
Hum well I don't know anything about these Nokia batteries, I only ever
met the GTA01 and now GTA02 smart batteries.
Can it be something stupid like the [-] [Temp] [+] pin ordering differs?
> By the way, it is my understanding that the coulomb counter is indeed a
> custom add-on for us, meaning that the standard BL-6C and other
> compatible batteries will in fact not work for us.
Well, the former may be true but the latter isn't -- the PMU is
blissfully unaware of the HDQ stuff. Its like some inbred country
cousin gas station attendant that will just fill up any car that stops
by if it has the gas tank cap in the right place. HDQ happens outside
of the charging system completely.
> In GTA01, how did we read the temp sensor? Was the analog to digital
> converter (ADC) an additional component, or are there any ADCs on the
> Samsung SoC? If the former, then I presume we don't have that chip on
> GTA02, which means we can not safely charge a battery without the
> coulomb counter, because we can't measure the temperature.
There are ADCs in the CPU, but GTA01 did it using an ADC in the PMU
itself. I never understood from the schematic if GTA02 has a thermistor
hooked up or not, it just shows a normal resistor there. But AIUI the
smart battery takes care of overtemp protection privately, additinoally
we can tell the battery pack temp over HDQ to 0.1 degrees C.
The datasheet for the smart bit of the smart battery shows a "Li-ion
protector" in the battery able to interrupt connectivity to the outside
world for the cell.
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