BAT32G1x9User Manual | Chapter 28 Standby function
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Rev.1.02
Chapter 28 Standby function
28.1 Standby function
The standby function is a function that further reduces the operating current of the system, and there are
two modes as follows.
(1)
Sleep mode
Sleep mode is the mode in which the CPU is stopped from running the clock. If the high-speed system
clock oscillation circuit, high-speed internal oscillator, or subsystem clock oscillation circuit is oscillating before
the sleep mode is set, the clocks continue to oscillate. Although this mode does not reduce the operating
current to the level of deep sleep mode, it is an effective mode for wanting to restart processing immediately
through interrupt requests or if you want to run frequently in intermittent operations.
(2)
Deep sleep mode
Deep sleep mode is a mode that stops the oscillation of the high-speed system clock oscillation circuit and
the high-speed internal oscillator and stops the entire system. The operating current of the CPU can be greatly
reduced.
Because deep sleep mode can be dismissed by interrupt requests, intermittent operations can also be
performed. However, in the case of the X1 clock, because the wait time to ensure oscillation stability is required
when decommissioning the deep sleep mode, it is necessary to select the sleep mode if you need to start
processing immediately through the interrupt request.
In either mode, registers, flags, and data memory are all left set to before standby mode, and the output
latches and output buffers of the input/output ports are also maintained.
Note 1 Deep sleep mode is only available when the CPU is running on the main system clock. When the CPU is running
on the subsystem clock, it cannot be set to deep sleep mode. Sleep mode can be used regardless of whether the
CPU is running on the main system clock or the secondary system clock.
2. When moving to deep sleep mode, WFI instructions must be executed after stopping peripheral hardware running
in the master system clock.
3. To reduce the operating current of the A/D converter, the bit7 (ADCS) of the A/D converter mode register 0 (ADM0)
must be placed) and bit0 (ADCE) clear "0",and execute the WFI instruction after stopping the A/D conversion run.
4. The option byte selects whether to continue or stop oscillation of the low-speed internal oscillator in sleep mode or
deep sleep mode. For details, please refer to "Chapter 35 Options Bytes".