If you take a look at the datasheet for the MAX3402E, it says that the slave select pin for SPI communications is active low. You need to set it to a logic low signal in order to put the IC in a state that is ready for SPI communications.
On page 11 of the datasheet, figures 8 and 9 show that to initiate a transaction, you need to set the ~SS pin low first and maintain the low signal until you are done with your SPI transactions.