SAF-C164SM Infineon Technologies, SAF-C164SM Datasheet - Page 402

• Manufacturer Part Number: SAF-C164SM
• Description: 16-Bit CMOS Microcontroller
• Manufacturer: Infineon Technologies

21.2
To further reduce power consumption, the microcontroller can be switched to Sleep
mode. Clocking of all internal blocks is stopped (RTC and selected oscillator optionally).
The contents of the internal RAM, however, are preserved through the voltage supplied
via the
Sleep mode is selected via bitfield SLEEPCON in register SYSCON1 and is entered
after the IDLE instruction has been executed and the instruction before the IDLE
instruction has been completed.
Sleep mode is terminated by interrupt requests from any enabled interrupt source whose
individual Interrupt Enable flag was set before the Idle mode was entered, regardless of
bit IEN. These are primarily external interrupts and the RTC (if running).
Note: The receive lines of serial interfaces may be internally routed to external interrupt
The realtime clock (RTC) can be kept running in Sleep mode in order to maintain a valid
system time as long as the supply voltage is applied. This enables a system to determine
the current time and the duration of the period in Sleep mode (by comparing the current
time with a timestamp stored when Sleep mode was entered). The supply current in this
case remains well below 1 mA.
During Sleep mode, the voltage at the
and its selected oscillator will continue running and the contents of the internal RAM will
be preserved. With the RTC (and oscillator) disabled the internal RAM is preserved down
to a voltage of 2.5 V.
Note: When the RTC remains active in Sleep mode, the oscillator which generates the
The total power consumption in Sleep mode depends on the active circuitry (whether the
RTC is on or off) and on the current flowing through the port drivers. Individual port
drivers can be disabled simply by configuring them for input.
The bus interface pins can be separately disabled by releasing the external bus (disable
all address windows by clearing the BUSACT bits) and switching the ports to input (if
necessary). The required software in this case must be executed from internal memory.
User’s Manual
inputs (see EXISEL). All peripherals except for the RTC are stopped and hence
cannot generate an interrupt request.
RTC clock signal will also continue running.
If the supply voltage is reduced, the specified maximum CPU clock frequency for
this case must be taken into account.
For wakeup (input edge recognition and CPU start) the power level must be within
the specified limits.
V
DD
Sleep Mode
pins. The watchdog timer is stopped in Sleep mode.
V
DD
21-6
pins can be lowered to 2.7 V while the RTC
Power Management
C164CM/C164SM
Derivatives
V1.0, 2002-02