SPRUJ79 November 2024 F29H850TU , F29H859TU-Q1
STANDBY is a more aggressive low-power mode that gates both the CPU clock and any peripheral clocks derived from PLLSYSCLK (based on STANDBYEN setting). The watchdog however, is left active. Like IDLE, this mode affects only one CPU subsystem. The other CPU subsystem and all of the peripherals are unaffected. STANDBY is good for an application where the wake-up signal comes from an external system (or CPU subsystem) rather than a peripheral input.
An NMI (or optionally) any interrupt or a configured GPIO can wake the CPU from STANDBY mode. Each GPIO from GPIO0-63 can be configured to wake the CPU when the GPIO are driven active low. Additionally a CMPSS based wake up can be used for coming out of standby mode by configuring CMPSSLPMSEL register.
IPC interrupt 1 (flag 0), an NMI fired to the other CPU, or (optionally) any interrupt, wakes the CPU subsystem up from STANDBY mode. Any of GPIO0-63 can also be configured to wake up the subsystem when the GPIO is driven active low.
To enter STANDBY mode:
To wake up from Standby mode:
At the end of the qualification period, the PLL enables the CLKIN to the CPU and the associated wake up interrupt is latched in the PIPE module.
The CPU is now out of STANDBY mode and can resume normal execution.