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| AT91SAM9R64 Datasheet, PDF (870/911 Pages) ATMEL Corporation – Thumb Microcontrollers | |||
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44.6 Core Power Supply POR Characteristics
Table 44-20. Power-On-Reset Characteristics
Symbol Parameter
Conditions
Min
Typ
Max
Units
VTH+
VTH-
TRES
Threshold Voltage Rising
Threshold Voltage Falling
Reset Time
Minimum Slope of +2.0V/30ms
0.70
0.85
1.08
V
0.60
0.80
1.00
V
80
150
230
µs
Figure 44-2. VVDDCORE and VVDDIO Constrains at Startup
VDD (V)
BMS sampling
VDDIO typ
VDDIO
VIH
VDDCORE typ
VTH+
VDDIO > Vih
VDDCORE
t
<--------------------- T1---------------------> <---- T2 ----> < T3 >
Core Supply POR output
SLCK
BMS sampling
Value of signals powered by VDDIO (such as BMS, NRST or I/O lines) will be unpredictable if
read when VVDDIO is lower than VIH. For correct operations VDDIO must have a minimum slope
at startup higher than VIH when BMS is sampled. After this, all signals will be correctly read.
Notes:
1. VDDIO stands for VDDIOPx or VDDIOMy.
2. VDDCORE typ, VDDIO typ and VIH are defined in Table 44-2, âDC Characteristicsâ.
3. T1 is given by the slope on VDDCORE power supply.
4. T2 = tRES
5. T3 = 3 x tSLCK
870 AT91SAM9R64/RL64 Preliminary
6289AâATARMâ15-Jan-08
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