TI E2E Community
Battery Management - Gas Gauge Forum
SMBus communication with bq20z90 gas gauge
I have a system in which I am using the bq20z90-150 gas gauge as a smart battery controller to communicate with a microcontrollerdriven battery charger via the SMBus. One of my customers has decided to use the bqEval software to read the battery performance during charging by jacking the EV2300 in parallel with the battery-to-charger connections. As a result, he is getting dropped data during continuous scans. Also, I am noticing that in data logs he is sending back to me, the Remaining Capacity Alarm and Remaining Time Alarm data cells in the SBS data are being corrupted. Is this due to trying to parallel-listen to the SMBus data by the EV2300 and our charger? What can I do for my customer to allow listening to the battery status while the battery is trying to talk to the charger?
When multiple masters try to read information from the slave battery, it is normal to see dropped data. bqEVSW will show blank data on SBS screen and in the log in this case. EV2300 handles SMB arbitration, so data should not be corrupt in the log. However if the other master on the bus does not adhere to arbitration as per SMB specification then it is possible to get corrupted dataHowever PEC is used by bqEVSW, so the data would be rejected in most cases when it is corrupted and will not logged.
Thanks for the answer on bus arbitration.
I still need to know what is causing the changing of the RCA and RTA values in the SBS data. As I understand it, the firmware reads the default value at startup from the data flash (.gg file). How is this value written over after the pack is started, and what are the ramifications of changing this value during operation?
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.