SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The SR3-APG power-management technology implements a fast power ramp-up technology. To take advantage of the fast ramp-up feature in SR3-APG, software must first enable it by setting the PRM_PSCON_COUNT[25] HG_RAMPUP bit to 1.
A fail-safe mechanism is put in place to revert back to the standard power ramp-up time by setting the PRM_PSCON_COUNT[25] HG_RAMPUP bit to 0.
The slow ramp-up time can be set through the PRM_PSCON_COUNT[23:16] HG_PONOUT_2_PGDOODIN_TIME bit field when the HG weak chain is used (in other words, the PRM_PSCON_COUNT[25] HG_RAMPUP bit is set to 0x0).
This applies only when SR3-APG is enabled (PRM_PSCON_COUNT[24] HG_EN = 1).
The L1 cache memory state depends on the values of the PRM_PSCON_COUNT[25] HG_RAMPUP and PRM_PSCON_COUNT[24] HG_EN bits. When CPU PD is in CSWRET state and HG_ENABLE and HG_RAMPUP are set to 0x1, L1 cache is in the ON state.
If SR3-APG is disabled (PRM_PSCON_COUNT[24] HG_EN = 0), the L1 cache array can be put in RETENTION during CSWRET regardless of the PRM_PSCON_COUNT[25] HG_RAMPUP bit.