SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The module wake-up feature is enabled when the MCSPI_SYSCONFIG[2] ENAWAKEUP and MCSPI_WAKEUPENABLE[0] WKEN bits are set. Wake-up capability is relevant only when the module is configured in slave mode.
The module generates an asynchronous wake-up request to the system power manager to switch back the interface clock and the functional clock. A wakeup is requested when channel 0 is enabled and an asynchronous selection occurs on the mcspim.csx port associated with channel 0 (see the definition for the MCSPI_CHxCONF[22:21] SPIENSLV bit field [where x = 0] in the register table description).
After the McSPI wake-up request, the system power manager must reactivate the interface clock:
Table 26-207 lists the supported cases in smart-idle mode.
Mode | Interface Clock | SPI Clock Ref | Functionality | Wake-Up Event |
---|---|---|---|---|
Master | Must be maintained | Must be maintained | Full functionality, but the module does not generate a new interrupt or DMA request until the system exits wake-up mode | No wake-up event |
Slave | Can be switched off | Can be switched off | An SPI word can be transmitted and/or received, but the module does not generate any new interrupts or DMA requests until the system exits wake-up mode. | The module asynchronously sends a wake-up request if an event on the SPIEN[x] port associated with channel 0 is detected. |
In wake-up mode, the interrupt and DMA request lines are no longer asserted.
Any access to the module in wake-up mode generates an error as long as the interface clock is alive.