SMBus Battery address

Sep 07, 2005 4 Replies
N

Hi,



I am trying to talk to a typical smart laptop battery from a 68hc12DJ64 processor on the I2C bus using the SMBus protocol. We just need to collect simple "how much charge is in there" data from the batter. The problem is that I dont know what is the address of the battery? Searched the internet and read through all the SMBus. I2c, motorola, battery specs but could not find any reference for finding battery address.



I am obviously missing something big time. Can someone tell me where to find the battery address?



Also, if you have talked to a battery using a 68hc12 before, can you share your experience.



Thanks Nihar



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N

The information you are looking for is in Appendix C of the SMBus Spec (SMBus20.pdf ).

Scott

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R

"Nihar" schrieb im Newsbeitrag news: snipped-for-privacy@g47g2000cwa.googlegroups.com...

Did you try to scan the bus by sending for x = 2 to 252 step 2

DeviceFound = AcknowledgeReceived next and see which devices are responding?

There are tools out with this kind of scanning built-in.

formatting link

Another alternative is to trace the bus as such when the battery is hooked to the laptop.

Best regards Roland

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N

Thanks! I did not expect such a fast reply! Yes it does say, 0001 011. The battery I am using is only compliant till v1.1. I believe the address would still remain the same. Also, what if there are more than one batteries?

thanks Nihar

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N

If their is more than 1 battery They all have the same address. You must use more than 1 Bus, or make a selector also in the smbus spec.

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