Micronas SDA 6000, User Manual

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SDA 6000
PRELIMINARY DATA SHEET
Version 2.1
System Control & Configuration
6 - 13 Micronas
6.4 Power Reduction Modes
Three power reduction modes with different levels of power reduction, which may be
entered under software control, have been implemented in M2:
Idle Mode: The CPU is stopped, while the peripherals including watchdog timer continue
their operation at low clock frequency.
Sleep Mode: CPU, peripherals and PLL are completely turned off. The controller ADC
operates in wake-up mode. The real-time-clock is still in operation.
Power Down Mode: All modules are turned off.
In the table above clocking frequencies have been specified, indicating that power
reduction is achieved by means of clock-gating. None of the power supplies are
internally switched, neither may voltage be turned off at the supply pins.
M2’s power management functions are supplemented by a Real Time Clock (RTC) timer
with optional periodic wake-up from idle mode. The periodic wake-up combines the
reduced power consumption in power reduction modes with a high level of system
availability. External signals and events can be scanned (at a lower rate) by periodically
activating the CPU and selected peripherals which then return to power-save mode after
a short time. This greatly reduces the system’s average power consumption.
Entering and Terminating Idle and Sleep Mode
All three modes are entered by writing register SLEEPCON (see register definition
below) and issuing the IDLE instruction. All external bus actions are completed before
entry to Idle, Sleep or Power Down mode. Normal operation is resumed after Idle mode
upon any interrupt request. To return from Sleep mode, external, wake up- or RTC-
Mode Normal Idle Sleep Power Down
Oscillator on on on off
PLL on on off off
CPU 33 MHz 3 MHz/
stopped
no clock/
stopped
no clock/
stopped
CADC 33 MHz
1)
1)
Conversion mode
3 MHz
2)
2)
Wake up mode
3 MHz
2)
off
RTC 3 MHz 3 MHz 3 MHz off
Peripherals 33 MHz 3 MHz off off
Bus Interface 100/66 MHz
3)
3)
Depending on value of CLKCON (see Chapter 8 )
off off off