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.
Sadly, I'm facing the same problem. Were you able to resolve the issue?
I'm using isoSPI and I have confirmed that the RDCFGA command (same one you've used) is transmitted correctly from the LTC6820 to the LTC6813-1. After receiving the mentioned command, the LTC6813-1 exits sleep mode for approx. 2 seconds (Vreg = 5 V during this time). So basically the exact same behaviour as you've described. I've already tried multiple SPI speeds (ranging from ~250 kHz to ~1 MHz).
The problem is that I never get a response from the LTC6813-1. Not getting a response (null) equals to a logic '1' and thus I only receive 0xFF eight times (6-bytes data and 2-bytes CRC).
Please check reply in another link: same question.