1) What is the maximum number I can connect to AD5232 in daisy chain mode.
2) Does the terminal AD5232 SDO in daisy chain need to back into the microcontroller?
1. There is no upper limit to the number of AD5232 that can be used in the daisy chain. All that matters is the timing specifications are met. Most critical are the SDI setup and hold time.
2. Having the last SDO connecting back the microcontroller helps to check all the configurations in register read back mode.