charging questions on ben

Adam Wang adam at qi-hardware.com
Tue Dec 1 23:04:20 EST 2009


Hi,

When I measured Ben's charging circuit, I have some questions for s/w
hacker:

a) how kernel know that the battery charging if done or in charing?
     Using ADIN0 (pin 92) of jz4720 to check voltage of VBAT? this pin is
directly connected to battery cell.
     If you use this to judge, how you manage s/w to shut down ben when
battery's voltage goes down under 2.94V?
     you can see [1] &[2], to know SHUTDOWN (GPD6) can tell cpu when
components U7 [3] found there's a low voltage detected,
     so means that you may need to do something on software to do store &
save tasks then turn off device.

b) has anyone used net name called "CHARGE_N" thus GPC27 (pin 69) of jz4720?
    what status did you initial this pin? input or output? have any help to
you?
    Why I asked these questions? Please see [4],

        ch1 = CHARGE_N / GPC27 of jz4720
	ch2 = pin 1 of U5 SE9016

I am thinking that using this "CHARGE_N" pin(GPC27) [5] as input then you
can let cpu known the status if charging is done or not by h/w, not judge
only by ADIN0; so then maybe you can code an icon at UI to let user know
that the device is at usb charging mode or battery mode.
Sorry I don't know s/w side. Thanks a lot.
Adam

[1]
http://downloads.qi-hardware.com/hardware/qi_avt2/v1.0/report/waveforms/lb60/lb60_12.jpg
[2]
http://downloads.qi-hardware.com/hardware/qi_avt2/v1.0/report/waveforms/lb60/lb60_waveform_description
[3]
http://downloads.qi-hardware.com/hardware/qi_avt2/v1.0/datasheet/U7~BL8506-30NRM.pdf
[4]
http://downloads.qi-hardware.com/hardware/qi_avt2/v1.0/report/waveforms/lb60/lb60_3.jpg
[5] http://wiki.qi-hardware.com/wiki/Power_Supply_Circuit
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