Ben Wilson wrote: > Svetoslav Trochev wrote: >> Ben Wilson wrote: >>>>> 5. SHR suspend, GSM on: 0.08A >>>>> >>>> This one looks strange, guys measured it to be ~45mA with uSD >>>> inserted and >>>> ~25mA without. >>>> >>> I measured ~45 / ~25mA most of the time but on two occasions I did see >>> ~75mA, i couldn't reproduce it though. >>> You do see some weird things current wise when gsm is on during >>> suspend. >>> >>> Psi. >>> >> I think I need more accurate meter here. My old Fluke 23 is only 3 1/2 >> digits and don't have needed resolution. I believe that suspend mode is >> failing to turn off some of the hardware in my case. I have not upgraded >> the firmware on my GSM module. Because the SSH connection between the >> Neo1973 and the host PC is dropped when the Neo is suspend I will need >> to connect the serial console to see the messages. Do I need to do >> something special to enable debug messages on the serial console or just >> connect the debug board? >> >> Thank you Psi, >> SAL-e >> > ya really need an oscilloscope to measure the current with GSM on, as > changes too much for a normal DMM to give an accurate reading. > I was using a scope across a resistor when i did my measurements.
Oh yes. I would love to have oscilloscope, but right now I might will able get my self a new DMM. If I get hold of something like Fluke 289/287, or 87V. I think one of them will do the job. Especially models 28x has data logging and graphs so we can monitor the change over boot time-line in to the addition of min/max/avg. Let me look around if I can rent one because I believe the price is in $500+ range for these puppies. > > Problem I found was the voltage loss in the wires and resistor at peak > current. The phone kept shutting off due to low voltage. Yes, That is why I used my 10A range, because the internal shunt resistor of Fluke 23 was about 0.1 Om only, if I remember correctly. And in addition I have only 1.5% + 2 counts accuracy so using for measuring the Neo1973's stand-by current is not appropriate at all. > > Ended up making this with some nice and thick wires. > http://psi.abcom.co.nz/fakebat.jpg > The contacts I used are out of an old Nokia phone (phone, not battery). That is really cool setup you have. I am going to build my self something like that also! :) > Even then I sometimes had to short out the shunt resistor until it had > booted up and suspended. > > Psi. > Thanks, SAL-e _______________________________________________ devel mailing list devel@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/devel
