atam510 ATMEL Corporation, atam510 Datasheet - Page 20

• Manufacturer Part Number: atam510
• Description: Marc4 4-bit Mtp Universal Microcontroller
• Manufacturer: ATMEL Corporation

2.7.5
20
ATAM510
Power-down Modes
Table 2-7.
Note:
The ATAM510 incorporates several modes which enable the power consumption to be tailored
to a minimum without sacrificing computational power. When the controller exits the lowest prior-
ity interrupt task, it reverts to a SLEEP state. This is a CPU shutdown condition which is used to
reduce average system power consumption where the CPU itself is only partially utilized. In
SLEEP, the CPU clocking system is deactivated whereby the peripherals and associated clock
sources may remain active (Standby Mode) or they can also be halted (Halt Mode). In Standby
Mode, the peripherals are able to continue operation and if required also generate interrupts
which can, along with a reset, reactivate the CPU to bring it out of the sleep state.
SLEEP can only be maintained when none of the interrupt pending or active register bits are set.
The application of the $AUTOSLEEP routine ensures the correct function of the sleep mode.
In both Standby and Active modes the current consumption is largely dependent on the fre-
quency of the CPU system clock (SYSCL) and the supply voltage (VDD) (see
Figure 7-4 on page
Selection of Standby or Halt mode is performed by the NSTOP bit in the clock management reg-
ister (CM). It should be noted that the low power 32-kHz crystal oscillator, if enabled will always
remain active in both Standby and Halt modes.
Table 2-8.
OS1, OS0
CCS
Standby
Mode
Active
0
0
0
0
1
Halt
If the bit CCS = 0 in the CM-register, the RC-oscillator 1 is stopped.
OS1
Oscillator selection bits (in conjunction with the CCS-bit)
Oscillator Select
Power-down Modes
CPU Core
1
0
1
0
x
SLEEP
SLEEP
State
RUN
64) while the Halt Mode current is merely controller static leakage current.
OS0
1
1
0
0
x
NSTOP
1
1
0
SYSCL
SYSCL
max
SUBCL
32 kHz
/64 or 32 kHz
4-MHz Oscillator
RC-Oscillator 1
RC-Oscillator 2
max
/64
STOP
RUN
RUN
System Oscillator Selection
External input clock at SCLIN
RC-oscillator 2 with R
4-MHz crystal oscillator
32-kHz crystal oscillator
RC-oscillator 1
Oscillator
32-kHz
RUN
RUN
RUN
ext
Clock at SCLIN
4711B–4BMCU–01/05
External Input
Figure 7-3
Disabled
Enabled
Enabled
and