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42073A-MCU Wireless-02/13
ATmega2564/1284/644RFR2
12.5 Supply Voltage and Leakage Control
For battery applications using DEEP_SLEEP periods, the leakage current defines the
system life time. Due to the typical strong temperature dependency of the leakage
current, major contributors to the leakage budget are turned off:
Analog and digital voltage regulator,
Non-volatile memory (NVM),
SRAM,
Digital signal processor of the radio transceiver including AES engine.
If the CPU uses one of the sleep modes “power-down” or “power-save”, the above
mentioned blocks will be switched off by power switches. When the CPU wakes up, the
blocks are switched on again. There are some additional exceptions (internal voltage
The supply voltage control is mainly hidden to the application, it is not necessary to
configure the supply voltage control. Nevertheless some configurations can be done in
order to get the maximum effect and the lowest sleep current, for details see section
12.5.1 Power-chain
The following figure shows the major dependencies of the power-chain and how the
power switches are situated inside the chain.
Figure 12-1. Power-chain connections
power_control
bandgap
DVREG
LLVREG
drt_switch
First SRAM
drt_switch
Last SRAM
power_switch
Radio
Transceiver
power_switch
NVM
powerchain_ ok
llvreg_ok
trx24_sleeps
Startup and Wakeup from DEEP_SLEEP
After power-on reset (POR) or wakeup from DEEP_SLEEP the power switches of the
blocks will be enabled one after another (power-chained) to decrease current peaks.
The blocks will be enabled in the following order:
1. Bandgap reference and voltage regulator,
2. Digital voltage regulator (DVREG) and low leakage voltage regulator (LLVREG),
3. first SRAM block (lower 4k bytes),
4. last SRAM block (upper 4k bytes),
5. Radio transceiver including AES engine,
6. Non-volatile memory.
If the power-chain is completely enabled the standard AVR wake-up procedure
continues.