AEK-COM-ISOSPI1 adding an extra bit before the message is sent

[AnthonyGran]

I'm working on a battery management system using an STM32F302 going to an AEK-COM-ISOSPI1 dev board using the L9963T transcevier which is daisy-chained to 10 AEK-POW-BMS63EN boards using the L9963E chip.

The problem that I'm having is that when I send a message over the ISO SPI lines, it adds an additional 0 before it sends the message.

I have attached two messages that show the leading 0 bit that is added. msg 0x55 55 55 55 55 and msg 0xFF 00 FF 00 FF. 

SPI settings are

8 bits frame 

MSB first 

Baud rate 1000 kbits/sec

CPOL low

CPHA 2 edge

CRC Disabled

How would I go about removing the leading zero from the message?

Any help would be great

Thanks

[SRomeo]

Hi Antony,
It seems you are acquiring ISOSPI data with a sampler; 
In order to help you with the analysis I need complete SPI signal waves.

Please probe the whole SPI signal (not ISOSPI) using a scope or a logic analyzer.
Make sure to acquire:

• CLK
• CS
• MOSI
• MISO (which should be inconsistent if you are not communicating with BMS)
  
  Here follows a real acquisition of SPI communication to enable an AEK BMS board:
  

  Best regards,
  Simone
  AEK_Team