Power modes in nrf51822

Question

HI, 
 Which are the main characteristics of the different power down modes (sleep, deepsleep, power down, deep power down and deep power down(PHY off))?

bjorn-spockeli · Accepted Answer

The nRF51 series has two power modes, System OFF and System ON, where System ON has a low power sub mode. The section below is quoted from the nRF51 Reference Manual, found here . 
 System OFF mode 
 
 System OFF is the deepest power saving
mode the system can enter. In this
mode, the system’s core functionality
is powered down and all ongoing tasks
are terminated. The only mechanism
that is functional and responsive in
this mode is the reset and the wakeup
mechanism. 
 The system can be woken up from System
OFF mode either from the DETECT signal
(when active) generated by the GPIO
peripheral, by the ANADETECT signal
(when active) generated by the LPCOMP
module, or from a reset. When the
system wakes up from OFF mode, a
system reset is performed. 
 
 System ON mode 
 
 System ON mode is a fully operational
mode, where the CPU and all
peripherals are brought into a state
where they are functional. In System
ON mode the CPU can either be active
or sleeping in the low power sub
mode . The CPU enters sleep by
executing the WFI or WFE instruction
found in the CPU’s instruction set. In
WFI sleep the CPU will wake up as a
result of an interrupt request if the
associated interrupt is enabled in the
NVIC. In WFE sleep the CPU will wake
up as a result of an interrupt request
regardless of the associated interrupt
being enabled in the NVIC or not. 
 The system implements mechanisms to
automatically switch on and off the
appropriate power sources depending on
how many peripherals are active, and
how much power is needed at any given
time. The power requirement of a
peripheral is directly related to its
activity level.The activity level is
usually raised and lowered when
specific tasks are triggered or events
generated, see individual chapters
describing the different peripherals
for more information on how to
optimize power consumption in System
ON mode. 
 
 Best regards 
 Bjørn