SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The internal pull resistors of pads gpmc_a[27:24, 22:19] can be permanently disabled by pulling sysboot15 high during power-on-reset deassertion. When sysboot15 = 1, the corresponding PULLUDENABLE bit does not apply anymore. In this case it is a don't care bit whatever value set. This functionality is intended to be used when mmc2_dat* signals are configured on the gpmc_a[27:24, 22:19] pads. In this case, if sysboot15 = 1, external pull-up resistors with values as per JEDEC eMMC specification (JESD84-B451) must be connected to these pads. If gpmc_a[27:24, 22:19] are connected to non-multiplexed NOR flash used for booting and sysboot15 = 1, external pull-down resistors are mandatory on these pads otherwise boot is not possible. During NOR flash run-time accesses the external pull-down resistors are not needed.