Figure 2-1 illustrates cell voltage calibration.

Figure 2-1 Cell Voltage Calibration

1. Apply known voltages in mV to the cell voltage inputs:
   • V_CELL1 between VC1 pin and VSS pin
   • V_CELL2 between VC2 pin and VC1 pin
   • V_CELL3 between VC3 pin and VC2 pin
   • V_CELL4 between VC4 pin and VC3 pin
2. If ManufacturerStatus()[CAL] = 0, send 0x002D to ManufacturerAccess() to enable the [CAL] flag.
3. Send 0xF081 or 0xF082 to ManufacturerAccess() to enable raw cell voltage output on ManufacturerData().
4. Poll ManufacturerData() until the 8-bit counter value increments by 2 before reading data.
5. Read the ADC conversion readings of cell voltages from ManufacturerData():

   ADC_CELL1 = BBbb of ManufacturerData()

   Is ADC_CELL1 < 0x8000? If yes, use ADC_CELL1; otherwise, ADC_CELL1 = –(0xFFFF – BBbb + 0x0001).

6. Average several readings for higher accuracy. Poll ManufacturerData() until ZZ increments, to indicate that updated values are available:

   ADC_CELL1 = [ADC_CELL1(reading n) + … + ADC_CELL1(reading 1)]/n

7. Average all of the cells to create a single cell gain with the average all voltages:

   Equation 1. $Cell Gain = \frac{V_{cell1}+V_{cell2}+V_{cell3}+V_{cell4}}{AD{C}_{cell1}+AD{C}_{cell2}+AD{C}_{cell3}+AD{C}_{cell4}}\times 2^{16}$
8. Write the new Cell Gain value to data flash.
9. Re-check voltage readings and if these are not accurate, repeat steps 4 – 8.
10. Send 0x002D to ManufacturerAccess() to clear the [CAL] flag if all calibration is complete.