in the view into registers in the device. The gg.csv files should not be edited with a spreadsheet program since
those may add characters causing the import to fail.
4.6.2 OTP Programming
CAUTION
OTP programming is a permanent change to the device. Be sure all configuration and calibration
are set before programming settings into the device. Casual programming may leave the board
inoperable. Writes to OTP are not incremental, all OTP is written at the same time.
Once the configuration and calibration has been determined and loaded in the registers, it may be programmed
to the BQ76922 OTP memory using the
Program OTP
button at the top of the pane. Note that this is a
permanent programming and is not reversible. There are 2 writes possible, if the device has been programmed
once, a second memory is available. Additional memories are not available. OTP memory is programmed using
the OTP memory view. Programming typically takes about 40 s. To program the OTP memory:
1. OTP write requires 12V at the board stack and room temperature. Calibrate the device if needed.
2. Be sure the desired settings are written to the data memory.
3. Select the Program OTP tool at the top of the Data Memory window. This opens a Program OTP pane.
4. Adjust the board voltage to 12.0 +/- 0.1 V for programming.
5. Select the Check OTP Programming Possible button. If not successful make the recommended adjustments
if possible. If successful, the display is similar to
6. Select the Program Data Memory to OTP Memory button. If successful, the display is similar to the check.
7. Adjust the board voltage back to normal operating conditions, cycle power, and test as desired.
Figure 4-7. Program OTP Pane with Success Display
4.7 Calibration
The calibration tool may not be available for all versions of devices. When the calibration tool is not available
calibration of the device can be performed by entering values in the calibration section of the data memory.
The calibration writes to the volatile registers in the device which are available in the Data Memory view. When
calibration values are complete they can be written to the OTP with other configuration settings. Calibration
cannot be written to OTP separately from configuration settings.
The EVM and all new boards should be calibrated before operation. The calibration view is shown in
.
Temperature is typically calibrated first. Board Offset should be calibrated with no current flow and should be
calibrated before Current Gain. The EVM uses a 1-mΩ sense resistor and calibration at low current results in
some granularity from the current resolution. This may result in an apparent error at higher currents. Calibration
at higher currents reduces this effect and should be done where it is important.
Voltages and temperatures may be calibrated individually or as a group. All values entered are calibrated. If
individual values are to be calibrated, leave all the other entries blank. As an example, measure the battery
voltage, calculate the average cell value and enter the value in the box. Clicking the Calibrate Voltage button
runs the calibration. Values left blank or entered as '0' are not calibrated. When successful, a green check
appears next to the button as shown in
. If there is an error, a red X appears instead as shown in
with a message in the bottom border.
Battery Management Studio Software
SLVU957A – SEPTEMBER 2019 – REVISED NOVEMBER 2021
BQ76922EVM Evaluation Module
11
Copyright © 2021 Texas Instruments Incorporated