Is there any document that explains what these pad types mean?
I've searched the Reference Manual and the Datasheet and the I/O spreadsheet. They all mention them, but I am not seeing an explanation of what they really mean.
e.g. the RM says:
"NOTE: Supported input levels vary according to pad types. Pad type "pad_sr_hv" supports only the
CMOS input level, while pad type "pad_isatww_st_hv" supports TTL and CMOS levels. Refer to
the attached IO spreadsheet for the pad type of each pin."
A web search just led me to the 5746R docs I already have.