BQ41Z50: Confusion about the relationship between InitialBatteryMode and BatteryMode register, and ability to change BatteryMode on the fly

I see this question also came up on the BQ40Z50:

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1204521/bq40z50-r2-bit-register-for-battery-mode-is-always-high-chgm-am

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1094005/bq40z80-why-can-t-the-chgm-and-am-bits-be-written-as-0

One of those posts implies that the ChgM and AM bits simply follow the BCAST bit, * BUT * according to the docs

ChgM == 0 allows broadcasts and 1 INHIBITS them, and same "polarity" is described for the AM bit.

Is the documentation wrong in both the 40Z50 and 41Z50 Technical Reference Manuals regarding what the values in ChgM and AM do?

If not, it seems like ChgM and AM (in BatteryMode) should automatically set themselves to the be the opposite of the BCAST bit.

(and it seems like the more correct behavior would be be for them to follow what is set in the InitialBatteryMode register).

Our application includes running the BQ41Z50 without an MCU in some scenarios, as described in SLUAAF8.

What are the correct settings to force the BQ41Z50 to send ChargingCurrent() and ChargingVoltage() commands?

If it is as simple as setting the BCAST bit and doing a RESET, then what other conditions could prevent the broadcasts from being sent?

Hello Kevin,
From BQ41z50 TRM, CHGM = 1 means BCAST is disabled. When you set BCAST, they will become 0-green. 

Kevin Banks said:

2. Is there some reason the BQ41Z50 would turn the ChgM and AM bits back on? (which INHIBITS sending these broadcasts).

You might need to check writing to initial batt mode under SBS config TAB. When you do a write here, it will take effect even if you POR/reset the device.

Jose: What you describe makes sense, but it is not the behavior I am seeing.

Even though I am setting CHGM and AM to green (0) in the InitialBatteryMode, and also setting the BCAST bit in the SbsConfiguration register, the CHGM and AM bits in the BatteryMode register remain red (1) and I also see no broadcasts from the BQ41Z50 on the logic analyzer (even after issuing a RESET command to the chip).

If I write BatteryMode with the CHGM and AM bits off, they are still set (red) when I read back the register.

These sorts of questions often result in a request for a "gg" file.

I assume the "*.gg.csv" file you get when you do Export from the Data Memory tab would do?

NewBoard082324ExportDataRegisters.gg.csv

I have tried various combinations of settings yesterday and this morning, but the attached file should be representative.

Thanks in advance for your help - Kevin Banks

Hi Kevin,

I am checking this feature internally. I will get back to you. 

Any estimate on a release date for the BQ41Z50 Broadcast Feature?