I'm constructing a battery tester for qualifying smart batteries in various handheld devices. So far I've had success in communicating with a variety of TI Gas Gauge chips in iPads, iPhones, Surface, and several Android tablets using I2C and HDQ.
But I've run up against a wall on this one: I've got a Dell tablet here that uses a battery with a BQ9000 gas gauge in it. This chip responds on I2C at addresses 0x0b and 0x8b but the registers do not seem to line up with any of the other chips I've talked to. I'm getting responses on register addresses 0x40, 0x42, 0x43, 0x50 - 0x5a, and 0x71. But none of them decode (at least not obviously) to the design capacity, or to any ASCII string, or to anything else I can identify.
I don't think I need any help in talking to the device; I've done a lot of that already with a lot of devices. But I'd like to get my hands on a datasheet describing what the registers are for the BQ9000. Maybe I need to knock on something to open up something else with useful info in it? I dunno.
Anyway, the obvious bits of Goole-fu have not helped. Neither have I had any luck poking around in linux kernel sources. I did find some ads for a piece of software sold by some overseas folks (Russian maybe?) that lists the BQ9000 as one of the battery chips it can reprogram. But that's as close as I've been able to get.
Any help over here?