Hi,
as mentioned in the datasheet, these are the max supported speeds:
DSPI is clocked by F40 or F80 (40 or 80MHz):
Baud rate is calculated as:
Min baud rate prescaler is 2:
Min baud rate scaler is 2:
If DBR (Double Baud Rate) is 1:
SCK baud rate = (80MHz / 2) * ((1+1)/2) = 40MHz
... which is also maximum for DSPI2, DSPI3, SPI1 and SPI2 as mentioned in the datasheet.
Regards,
Lukas