BQ27Z558: Unseal command and TS pin

Tool/software:

Hello,

I have three questions regarding the BQ27Z558 fuel gauge:

1. Unseal / Full Access timing:
   When sending the two-step unseal or full access command sequence, I found that the gauge only responds correctly if I insert delays that match what BQStudio does: ~30 ms between the 1st and 2nd command, and ~3 s after the 2nd command before issuing further commands.

   • If I shorten either of these delays, the unseal does not work.

   • Why are these specific timing requirements necessary? Are they strict hardware/firmware needs of the device, or just conservative delays chosen by BQStudio?

2. TS pin if unused / internal temperature sensing:
   If I do not plan to use an external thermistor:

   • Should the TS pin be tied directly to GND, or pulled down with a resistor (e.g. 10 kΩ)?

   • Can I leave TS floating if I configure the gauge to use internal temperature sensing?

   • When the device is set to use internal temperature sensing, how exactly is the TS pin handled inside the IC? Does it become ignored, or must it still be tied to a defined level?

3. Temperature configuration address mismatch:
   I noticed that the manufacturer access (MFR) command address for the Temperature Enable configuration differs between the datasheet/manual and what BQStudio uses.

   • In the Technical Reference Manual it is shown at address 0x471D, but in BQStudio it writes to address 0x4721

   • Which one is correct? Is the documentation out of date, or does BQStudio override this setting in a different register?

Thanks in advance for clarification.