SN32F760 Series
32-Bit Cortex-M0 Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 67
Version 2.0
All GPIO pins can be served as DPDWAKEUP pins. However, the DPDWAKEUP pins which are used to wake up MCU
shall be set as input pull-up and keep in HIGH level before entering Deep power-down mode. The user must program
the GPIO registers for each pin to set the appropriate GPIO status (input pull-up, input pull-down, input floating, output
high, and output low, open-drain) and then program
register to latch the status of all GPIO pins.
When any of the DPDWAKEUP pins is pulled LOW, MCU wakes up from Deep power-down mode. The on-chip voltage
regulator will be turned on, and when the core voltage reaches the power-on-reset (POR) trip point, a system reset will
be triggered and the chip re-boots.
Once the chip has rebooted, the user can read
register to verify that the reset was caused by a wake-up
event from Deep power-down and was not a cold reset. If MCU wakes up from Deep power-down mode, the user must
program GPIO registers with the same settings (input pull-up, input pull-down, input floating, output high, and output
low) and then program
register to release the status of all GPIO pins.
The RESET pin has no functionality in Deep power-down mode.
4.3.3.1
Entering Deep power-down mode
Follow these steps to enter Deep power-down mode from Normal mode:
1.
Disable analog IP (ADC, LCD, HXTAL, LXTAL), External reset, SWD.
2.
Setup the desired GPIO status of all GPIO pins. The DPDWAKEUP pins which are used to wake up MCU shall
be set as input-pull up and keep in HIGH level. (Strongly recommended to set output high first, and then set as
input pull-up to reduce pull-up time)
3.
(Optional) Save data to be retained during Deep power-down to the DATA bits in Backup registers.
4.
register to latch the status of all GPIO pins.
5.
6.
Time spent between step 1 and step 5 shall longer than 20 us.
7.
Execute ARM Cortex-M0 WFI/WFE instruction.
After step 7, the PMU turns off the on-chip voltage regulator and waits for a wake-up signal from the DPDWAKEUP
pins.
4.3.3.2
Exiting Deep power-down mode
Follow these steps to wake up the chip from Deep power-down mode:
1. Any of the DPDWAKEUP pins level is from HIGH to LOW.
– The PMU will turn on the on-chip voltage regulator. When the core voltage reaches the power-on-reset (POR)
Trigger point, a system reset will be triggered and the chip reboots.
– All registers will be reset, except the Backup registers and PMU_CTRL register.
register to verify that the reset was caused by a wake-up event from Deep power-down and
was not a cold reset.
4. (Optional) Read the stored data in the backup registers.
5. Setup the same GPIO status of all GPIO pins as step 2 of 4.3.3.1.
6. Write 0x5A5A0001 to
register to release the status of all GPIO pins.
7. Setup the PMU for the next Deep power-down cycle.
