Hi,
Could you help me to clarify two BQ27421-G1x question?
(1.) How could I send the IT_enable command when I doing the Qmax learning??
- below information from "Low-Power, Long Runtime Battery Fuel Gauging Scheme.pdf " document.
3.1 bq27421-G1 Qmax Learning Scheme
The following sequence is recommended for the bq27421-G1 fuel gauge:
1. The host detects that the adapter is plugged in and disallows charging immediately.
NOTE: It is important to minimize any current flow during the next step.
2. The host then:
(a) Wakes the gauge.
(b) Waits approximately 4 seconds for initialization (the INITCOMP bit is set).
(c) Sends the IT_ENABLE command.
(d) Waits for the RUP_DIS bit to clear. This indicates the gauge has taken an OCV measurement to be
used for Qmax updates.
(e) Sends the SEALED command.
3. The gauge remains active and charging is allowed. Gauge coulomb counts throughout battery
charging.
4. After charge termination is reached, there will be two methods to allow a Qmax update:
• Traditional Qmax update: Leave the gauge awake until the VOK bit clears. This indicates the
second OCV measurement was taken. If all Qmax update conditions were met, then Qmax has
been learned. This typically takes 30 to 60 minutes, but could take as long as 2 hours.
• Fast Qmax update: This method does not require waiting until the VOK bit clears, but does require
the gauge to remain awake until Qmax is updated. If the previous steps were followed and a
discharge is started after charge termination, but before VOK clears, then Qmax will be updated.
5. The host stores this learned Qmax Cell 0 value before putting the gauge in SHUTDOWN mode and
then restores it along with the other configuration parameters every time it exits the SHUTDOWN
mode.
(2.) Do I need to send the reset command after I program the .DFFS file into gas gauge?
because I fond the data flash parameter will be reset to default by reset command even I program the .dffs file with new parameter!
Stanley