SAM3SD8C Atmel Corporation, SAM3SD8C Datasheet - Page 281

• Manufacturer Part Number: SAM3SD8C
• Manufacturer: Atmel Corporation

16.4.5
16.4.5.1
Figure 16-3. Raising the VDDIO Power Supply
16.4.6
281
281
Zero-Power Power-On
Backup Power Supply
Reset Cell output
Core Power Supply
Oscillator output
Oscillator output
22 - 42 kHz RC
vddcore_nreset
periph_nreset
Fast RC
proc_nreset
bodcore_in
SAM3S8/SD8
SAM3S8/SD8
Core Reset
Power Supply Reset
Raising the Power Supply
NRST
vr_on
Note: After “proc_nreset” rising, the core starts fecthing instructions from Flash at 4 MHz.
As soon as the voltage VDDIO rises, the RC oscillator is powered up and the zero-power
power-on reset cell maintains its output low as long as VDDIO has not reached its target voltage.
During this time, the Supply Controller is entirely reset. When the VDDIO 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 voltage regulator is enabled. The core power supply rises and the brownout
detector provides the bodcore_in signal as soon as the core voltage 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.
The Supply Controller manages the vddcore_nreset signal to the Reset Controller, as described
previously in
Zero-Power POR
Section
16.4.3. The vddcore_nreset signal is normally asserted before shutting
7 x Slow Clock Cycles
T
Regulator
ON
Voltage
3 x Slow Clock
Cycles
3 x Slow Clock
Cycles
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12
6.5 x Slow Clock
Cycles