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C161U
System Control Unit (CSCU)
Preliminary Data Sheet
384
02.2000
PRELIMINARY
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Clock Management Module
This block mainly controls the flexible clock management, which is represented by the
register SYSCON2. Programmable system slowdown operation is achieved by dividing
the oscillator clock by a programmable prescaler factor (1...32) resulting in a low
frequency device operation which significantly reduces the overall power consumption.
The PLL may be completely switched off in this mode. This module also controls the
oscillator selection (main or auxiliary) for Real Time Clock and for Slow Down Divider.
During Power Down mode, this block controls the operation of RTC and ports.
Register in Clock Management Module:
Note: SYSCON2 is a protected register; it’s security level is automatically set to full write
protection after execution of EINIT instruction.
Peripheral Management Module
Flexible peripheral management provides a mechanism to enable and disable each
peripheral module separately. In each situation (eg. idle mode, several system operating
modes, slow down mode, etc.) only those peripherals may be kept running which are
required for the respective functionality. All others can be switched off. It also allows the
operation control of whole groups of peripherals including the power required for
generating and distributing their clock input signal. Other peripherals may remain active,
eg. in order to maintain communication channels. The registers of separately disabled
peripherals can still be accessed.
The standard Idle mode can be additionally configured by programming the SYSCON3
register, using the flexible peripheral management functions. This is especially
advantages, because it is thus possible to activate only these peripherals also in Idle
mode which are really required for standby operation or for wakeup, reducing power
consumption to the absolute minimum for a specific peripheral operation during Idle
mode.
Register
Description
SCUSLC
SCU security level command register
SCUSLS
SCU security level status and password register
EXICON
EXISEL
ISNC
FOCON
Frequency output control register
Register
Description
SYSCON2
System configuration control register for clock management