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Check for continuity between cell inputs, balance inputs, 3 V, 5 V, fused VBAT+ and fused VBAT-. All of these nets should be isolated from each other.
Connect the BMS carrier to the AFE isoSPI port A.
Connect the AFE to 12 cells in series, OR connect a power supply between VBAT+ and VBAT-. The power supply can be set to about 30 V with a current limit of about 100 mA.
Toggle the CS pin of the AFE isoSPI from the BMS carrier constantly with a delay of about 1 s.
Measure the voltage between 3 V and VBAT-, and 5 V and VBAT-.
Turn off the power supply.
Battery Stack Monitor (LTC6811-1)
isoSPI Communication
Any commands sent to the LTC6811 require a PEC. Details can be found on page 53 of the datasheet and sample code on page 76. Additionally, if the LTC6811 has not received a command for 2 s, it will enter a sleep state and can be woken up by toggling the CS pin low and high before sending the command.
Connect the isoSPI port A to a BMS carrier board.
Power the BMS carrier board with 12 V.
Supply about 30 V between VBAT+ and VBAT-, or connect the AFE to 12 cells in series.
Send the RDCFGA command (00000000 00000010) from the BMS carrier to the AFE over SPI/isoSPI.
The AFE should respond by sending 6 bytes of data back to the BMS carrier:
Register | Bit 7 | Bit 6 | Bit 5 | Bit 4 | Bit 3 | Bit 2 | Bit 1 | Bit 0 |
|---|---|---|---|---|---|---|---|---|
CFGR0 Expected: | GPIO5 1 | GPIO4 1 | GPIO3 1 | GPIO2 1 | GPIO1 1 | REFON 0 | DTEN 1 | ADCOPT 0 |
CFGR1 Expected: | VUV[7] 0 | VUV[6] 0 | VUV[5] 0 | VUV[4] 0 | VUV[3] 0 | VUV[2] 0 | VUV[1] 0 | VUV[0] 0 |
CFGR2 Expected: | VOV[3] 0 | VOV[2] 0 | VOV[1] 0 | VOV[0] 0 | VUV[11] 0 | VUV[10] 0 | VUV[9] 0 | VUV[8] 0 |
CFGR3 Expected: | VOV[11] 0 | VOV[10] 0 | VOV[9] 0 | VOV[8] 0 | VOV[7] 0 | VOV[6] 0 | VOV[5] 0 | VOV[4] 0 |
CFGR4 Expected: | DCC8 0 | DCC7 0 | DCC6 0 | DCC5 0 | DCC4 0 | DCC3 0 | DCC2 0 | DCC1 0 |
CFGR5 Expected: | DCTO[3] 0 | DCTO[2] 0 | DCTO[1] 0 | DCTO[0] 0 | DCC12 0 | DCC11 0 | DCC10 0 | DCC9 0 |