General
Review and verify the following for the custom schematic design:
- Above sections, including relevant application notes and FAQ links
- Pin connectivity requirements, pin attributes, and signal description
- Standards referenced in the electrical characteristics including recommended operating conditions and any additional available information
- IO buffer type implemented and the allowed supply configuration (LVCMOS fixed (1.8V or 1.8V/3.3V) or SDIO dynamic voltage switching)
- Connection of valid supply to all the IO supply for IO groups (VDDSHVx or VDDSx or VDDS_WKUP)
- Sequencing of the IO supply
- Connection of processor DDRSS PHY IO supply based on the selected memory
Schematic Review
Follow the below list for the custom schematic design:
- Attached device IO supply and the IO supply for IO group referenced by the interface signals are connected to the same supply source
- Pullups are connected to the same supply rail that is connected to the processor VDDSHVx or VDDSx or VDDS_WKUP and attached device
- Connecting the 3.3V supply that is connected to the PMIC input, directly to the processor IO supply for IO groups VDDSHVx is not recommended since the IO supply is available for an undefined time in case the PMIC does not start-up and generate the other processor supply rails
Additional
- Note the power sequencing requirements based on the IO supply for IO groups voltage level used
- Dynamic voltage switching are supported by specific IO supply for IO groups (VDDSHV2, VDDSHV3, and VDDSHV4)
- Dynamic voltage switching of the IO supply for IO groups referenced to LVCMOS IO buffers are not allowed (VDDSHV0, VDDSHV1)