working：slave mode、4 lines
(B) is right or (C) is right？
Hi @joshua9264
Both configurations are valid.
By default, the LPSPI interface operates according to Option B, where:
- SIN as the input data line, connected to the master's output.
- SOUT as the output data line, connected to the master's input.
However, it is also possible to swap the data pin directions so that SOUT is used as the input data line and SIN is used as the output data line, which corresponds to Option C. To achieve this configuration, you need to set the CFGR1[PINCFG] field accordingly.
BR, VaneB