4-wire SPI problem with LTC6813-1

We are trying to communicate with  the LTC6813-1 on demo board DC2350A-B via 4-wire SPI from a 3.3V microcontroller host with  5V-compatible inputs.

After addressing /CSB  for 500µs, Vreg turns on for 2 seconds. When transmitting read command RDCFGA there is no answer on MISO.

The SPI configuration is following: Speed 1MHz and mode 1,1.

Command RDCFGA: Byte0: 0x00, Byte1: 0x02, Byte2: 0x2B, Byte3: 0x0A, Byte4-11:0x00 (to get clock for 12 bytes).

The /CSB  is set low before sending and set high after  12 bytes. No answer from LTC6813.


Configuration DC2350A: SDO pullup to VDD (tried 3.3 and 5V), all jumpers JP1-JP4 in 0-position, 18 cells Li-NMC connected, ISO-SPI not used.