Cypress FM4 Series - Operations in Deep Standby Modes

CHAPTER 6: Low Power Consumption Mode
FM4 Peripheral Manual, Doc. No. 002-04856 Rev. *E 219
5. Operations in Deep Standby Modes
This section explains the operations in deep standby modes.
There are two deep standby modes: deep standby RTC mode and deep standby stop mode.
Clock Operation States in Deep Standby Mode
The table below shows the respective states of the oscillator clocks, CPU clock, AHB bus clock and APB
bus clocks in deep standby RTC mode and deep standby stop mode.
Table 5-1 Clock Operation States in Deep Standby Mode
Deep Standby RTC Mode
Deep Standby Stop Mode
High speed CR clock
Stopped
Stopped
Main clock
Main PLL clock
Low speed CR clock
Sub clock
Operating
USB PLL clock
Stopped
I
2
S PLL clock
GDC PLL clock
CPU clock
AHB bus clock
APB0 bus clock
APB1 bus clock
APB2 bus clock
Factors for Returning from Deep Standby Mode
This section shows factors for returning from deep standby RTC mode and deep standby stop mode.
Table 5-2 Factors for Returning from Deep Standby Mode
Deep Standby RTC Mode
Deep Standby Stop Mode
Factor for returning from
deep standby mode
− INITX pin input reset
− Low voltage detection reset
− INITX pin input reset
− Low voltage detection reset
− Low voltage detection interrupt
− RTC interrupt
− HDMI-CEC/Remote Control Reception
interrupt
− Low voltage detection interrupt
− WKUP pin input
− WKUP pin input
Note:
− After the CPU has returned from a deep standby mode, the interrupt factor is retained. However,
since NVIC is initialized by the deep standby transition reset, no interrupt processing is to be
executed.