SAM3X8E Atmel Corporation, SAM3X8E Datasheet - Page 280

• Manufacturer Part Number: SAM3X8E
• Manufacturer: Atmel Corporation

17.4.6
17.4.6.1
Figure 17-5. Raising the VDDUTMI Power Supply
280
280
Zero-Power Power-On
Backup Power Supply
Reset Cell output
Core Power Supply
Oscillator output
Oscillator output
22 - 42 kHz RC
vddcore_nreset
SHDN / vr_on
periph_nreset
Fast RC
proc_nreset
bodcore_in
SAM3X/A
SAM3X/A
Backup Power Supply Reset
Raising the Backup Power Supply
NRST
Note: After “proc_nreset” rising, the core starts fecthing instructions from Flash at 4 MHz.
As soon as the backup voltage VDDUTMI rises, the RC oscillator is powered up and the zero-
power power-on reset cell maintains its output low as long as VDDUTMI has not reached its tar-
get voltage. During this time, the Supply Controller is entirely reset. When the VDDUTMI voltage
becomes valid and zero-power power-on reset signal is released, a counter is started for 5 slow
clock cycles. This is the time it takes for the 32 kHz RC oscillator to stabilize.
After this time, the SHDN pin is asserted and the voltage regulator is enabled. The core power
supply rises and the brownout detector provides the bodcore_in signal as soon as the core volt-
age VDDCORE is valid. This results in releasing the vddcore_nreset signal to the Reset
Controller after the bodcore_in signal has been confirmed as being valid for at least one slow
clock cycle.
Zero-Power POR
7 x Slow Clock Cycles
T
Regulator
ON
Voltage
3 x Slow Clock
Cycles
3 x Slow Clock
Cycles
11057A–ATARM–17-Feb-12
11057A–ATARM–17-Feb-12
6.5 x Slow Clock
Cycles