Q
Do I need an external pull up resistor on the SDO pin if the Busy Indicator
feature is not required?
A
No. An external pull up resistor is only required if the Busy Indicator feature
is used. When the Busy Indicator feature is used the SDO pin goes from
three-state to active low at the EOC point. To ensure this change can be
detected by the input to a controller the pull up resistor ensures the
three-state condition is seen as a high level at the controller.