SPRUI33H November 2015 – June 2024 TMS320F280040-Q1 , TMS320F280040C-Q1 , TMS320F280041 , TMS320F280041-Q1 , TMS320F280041C , TMS320F280041C-Q1 , TMS320F280045 , TMS320F280048-Q1 , TMS320F280048C-Q1 , TMS320F280049 , TMS320F280049-Q1 , TMS320F280049C , TMS320F280049C-Q1
The active grace period (AGP) can be used to optimize the Flash module power consumption versus access time. Faster access times are associated with higher-power modes of operation. At one extreme, the power control logic can attempt to reduce power consumption by putting the bank and charge pump into a low-power mode immediately at the end of every Flash access. However, if accesses are only a few cycles apart, this can actually increase power consumption versus leaving the Flash powered, because the bank and charge pump consume more power during Flash startup and access.
The active grace periods (supported for Bank0 and Bank1 together, in addition to the charge pump module) allow the banks and/or charge pump to be maintained in active mode for a specified period following an access. This is done in anticipation of another read within the AGP time, to allow the subsequent read to have a faster access and spend less time dissipating power, than if the bank went into one of the low power modes immediately. If the next access does not occur within the AGP time, the power control logic can automatically put the bank and/or charge pump into a low-power mode to reduce power consumption during long periods of inactivity.
The AGP value is programmed by a set of programmable counters (FBAC and FPAC2) that keep the Flash bank or charge pump in active mode until the counter expires, at which time the bank or charge pump reverts to the fallback power mode as defined in the FBFALLBACK and FPAC1 (refer to PMPPWR bit-field) registers. The application software can configure the fallback power mode to reduce power consumption, or configure the fallback power mode to be in active mode to keep the bank active regardless of counter settings (default is SLEEP). The charge pump AGP counter remains in the initialized state when the bank is active, including the AGP counter of the bank. The charge pump AGP counter begins counting when the bank has become inactive.
The application software can check the current power mode of Flash bank and charge pump by reading the FBPRDY register. Refer to Section 3.15 for detailed information.