I am using an LTC2313-12 in combination with an ESP32 using (V)SPI functionality of the ESP32.
According to the description in the datasheet (https://www.analog.com/media/en/technical-documentation/data-sheets/231312fb.pdf -- p10/22 - Serial Interface) and the graph (p11/22 - Timing diagram), the MSB should be available on first SCK falling edge.
When sending 2 bytes (2 x 8 bits) via SPI, I can measure that the SCK line sends 2 x 8 pulses to the LTC2313-12, while the CONV is LOW. Looking at the SDO line at the same moment, it is noticed that the MSB appears at the second SCK falling edge and not, as noted in the datasheet, with the first SCK falling edge. The LSB than coincides with the 14Th SCK pulse = 6Th pulse of the second byte).
I can resolve this by taking the last 6 bits of the MSbyte and attach to this MSbyte the first 6 bits of the LSbyte (Result = MSbyte <<6 | LSbyte >>2. This gives me the required result over the complete range (obtaining a high speed 0000 - 4096 output for 0.0V to 2.048V input), but it feels wrong that the result is not as predicted by the datasheet.
Changing SPI divider 2x, 4x, 8x, ... does not change the result.
Is the datasheet wrong, or am I doing something wrong ?