Using a Logic Analyzer

Thread Starter

brightnight1

Joined Jan 13, 2018
50
I have a camera that does a battery athentification before being powered on by the battery. I would like to know how the camera is authentificating the battery and replicate it so I can power the camera with a different (much larger) DC source. I have access to a decent logic analyzer to look at the communication between the battery and the camera but wondering how would I know what the communication protocol will be? I'm not familar with logic analyzers so perhaps I can take a reading and then try to decode my measurement in different protocols until something works. I'd guess I2C or SMBUS but is there a better way then guess and check?
 

KeithWalker

Joined Jul 10, 2017
460
There will be either a comparator that checks the battery voltage and gives the processor either a 1 or a 0, or an A/D that measures the battery voltage..
You don't need to mess with the programming. Just connect a suitable power supply to where the battery makes contact.
Regards,
Keith
 

Thread Starter

brightnight1

Joined Jan 13, 2018
50
There will be either a comparator that checks the battery voltage and gives the processor either a 1 or a 0, or an A/D that measures the battery voltage..
You don't need to mess with the programming. Just connect a suitable power supply to where the battery makes contact.
Regards,
Keith
I intiially tried just connecting a DC supply with the right voltage to the V+ and V- contacts but that didn't work so I started digging deeper. I really need to open up a battery to see what pin the thermistor and comms pin is.

Here's what I found online:
"The battery is also polled for an authentication response. 1-Wire communication is going on between these two, but we haven't looked into the protocol yet. Right now I believe it's just a, "are you there?" Just FYI the 4 lines leading up to the battery are BATT+, BATT-, Thermistor, one-wire comm."
 

440-8pak

Joined May 15, 2010
1
This reminds me of a hand held label printer we had at work. The paper roll had to be from that specific manufacturer for the printer to function. The paper roll had a Dallas/Maxim DS2430A 1 wire EEPROM inside it with a slip ring so it could turn and maintain communication with the microcontroller. I wouldn't be surprised it you find one of these in your battery pack!
 
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