SN32F260 Series
32-Bit Cortex-M0 Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 49
Version 1.5
Wake up the chip from Sleep mode by an interrupt occurs.
The RESET pin has keep functionality in Sleep mode.
The Sleep mode is entered by using the following steps:
1. Write 4 to
2. Execute ARM Cortex-M0 WFI instruction.
4.3.2 DEEP-SLEEP MODE
In Deep-sleep mode, the system clock to the ARM Cortex-M0 core is stopped, and execution of instructions is
suspended.
The clock to the peripheral functions are stopped because the power state of oscillators are powered down, the clock
source are stopped.
The processor state and registers, peripheral registers, and internal SRAM values are maintained and the logic levels
of the pins remain static.
All GPIO pins are served as wakeup pins. The user must program the GPIO registers for each pin to set the
appropriate edge polarity for the corresponding wakeup event, only edge sensitive is supported to wakeup MCU. The
system will exit Deep-sleep mode when GPIO indicates a GPIOn interrupt to the ARM core. Furthermore, the interrupts
corresponding to each input must be enabled in the NVIC. Wake up time is 56us at the VDD = 3.3V.
The RESET pin has keep functionality in Deep-sleep mode.
The Deep-sleep mode is entered by using the following steps:
1. Write 2 to
2. Execute ARM WFI instruction.
The advantage of the Deep-sleep mode is that can power down clock generating blocks such as oscillators, thereby
gaining far greater dynamic power savings over Sleep mode. In addition, the Flash can be powered down in
Deep-sleep mode resulting in savings in static leakage power, however at the expense of longer wake-up times for the
Flash memory.
4.4 WAKEUP
4.4.1 OVERVIEW
Under low power
mode, program doesn’t execute. The wakeup trigger can wake the system up to normal mode. The
wakeup function builds in interrupt operation and trigger system executing interrupt service routine as system wakeup
occurrence.
The wakeup trigger sources of the Sleep mode are all interrupts and the RESET pin.
The wakeup trigger sources of the Deep-sleep mode are the GPIO interrupt, CT16B0/1 interrupt, and the RESET
pin.
4.4.2 WAKEUP TIME
When the system is in Sleep mode, the high clock is enabled or disabled by F/W. If the high clock stops and MCU is
waken up from Sleep mode, MCU waits for 2048 external high-speed oscillator clocks and 32 internal high-speed
oscillator clocks as the wakeup time to stable the oscillator circuit. After the wakeup time, the system goes into the