at91sam9g20-cu ATMEL Corporation, at91sam9g20-cu Datasheet - Page 771

• Manufacturer Part Number: at91sam9g20-cu
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

41.8
Table 41-23. Power-On-Reset Characteristics
41.8.1
41.8.2
6384B–ATARM–15-Dec-08
Symbol
V
V
T
th+
th-
RES
Core Power Supply POR Characteristics
Power Sequence Requirements
Power-up Sequence
Parameter
Threshold Voltage Rising
Threshold Voltage Falling
Reset Time
The AT91SAM9G20 board design must comply with the power-up and power-down sequence
guidelines below to guarantee reliable operation of the device. Any deviation from these
sequences may lead to the following situations:
Figure 41-2. VDDCORE and VDDIO Constraints at Startup
VDDCORE and VDDBU are controlled by Power-on-Reset (POR) to gurantee that these power
sources reach their target values prior to the release of POR. (See
• Excessive current consumption during the power-up phase which, in the worst case, can
• Prevent the device from booting.
• VDDIOM and VDDIOP must NOT be powered until VDDCORE has reached a level superior
• VDDIOM and VDDIOP must be ≥ 0.7V within (T2 + T3) after VDDCORE reaches
• VDDIOM and VDDIOP must reach Voh (2.6V) within (T2 +T3 +T4) after VDDCORE has
result in irreversible damage to the device.
or equal to Vth+ (0.5V).
Vth+ (0.5V).
reached Vth+ (0.5V).
VDDCOREtyp
V th+ (0.5V)
Core Supply POR output
V oh (2.6V)
VDDIOtyp
VDD (V)
SLCK
0.7V
Conditions
Minimum Slope of +1.0V/100ms
<--------------------- T1--------------------->
AT91SAM9G20 Preliminary
<T2>
<T3>
<-------------T4----------->
Min
0.5
0.4
30
Typ
0.7
0.6
Figure
70
VDDIO > V oh
41-2.)
VDDCORE
VDDIO
Max
0.89
0.85
130
t
Units
µs
V
V
771