ATSAM3U-EK Atmel, ATSAM3U-EK Datasheet - Page 13

• Manufacturer Part Number: ATSAM3U-EK
• Description: KIT EVAL FOR AT91SAM3U CORTEX
• Manufacturer: Atmel
• Type: MCUr

Specifications of ATSAM3U-EK

• Contents: Board
• Processor To Be Evaluated: SAM3U
• Data Bus Width: 32 bit
• Interface Type: RS-232, USB
• Operating Supply Voltage: 3 V
• Silicon Manufacturer: Atmel
• Core Architecture: ARM
• Core Sub-architecture: Cortex - M3
• Silicon Core Number: SAM3U4E
• Silicon Family Name: SAM3U
• Kit Contents: Board CD Docs
• Rohs Compliant: Yes
• For Use With/related Products: AT91SAM3U
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4.3.4
SAM3U-EK Evaluation Kit User Guide
Reset and Wake-Up Circuitry
Figure 4-4.
The on-board NRST button BP1 and NRSTB button BP2 provide the SAM3U4E with external reset con-
trol. The on-board WAKE-UP button BP3 can be used to wake up the chip from low power modes.
Figure 4-5.
The NRST pin is bidirectional. It is handled by the on-chip reset controller. It can be driven low to provide
a reset signal out to the external components. Conversely, it can be asserted low from the outside to
reset the microcontroller, its core and peripherals, Backup region (RTC, RTT and Supply Controller)
excepted. The NRST pin integrates a permanent pull-up resistor of about 100 kOhm to VDDIO.
On the SAM3U-EK board, the NRST signal is connected to the LCD module and JTAG port.
The NRSTB pin is an input-only signal that enables the asynchronous reset of the SAM3U4E series
when asserted low. The NRSTB pin integrates a permanent pull-up resistor of about 15 kOhm. This
allows the connection of a simple push button for implementing a system-user reset. Whatever the
mode, this pin will reset the chip including the Backup region (RTC, RTT and Supply Controller). It
makes the chip behave as for a Power-on reset. An external capacitor (10 nF) is connected between
NRSTB and VDDIO to enforce the signal stability on this pin.
XIN32
XOUT 32
XIN
XOUT
External Clock Source
System Buttons
2
4
NR S T
NR S T B
F W UP
J 1 J 1
XIN32
XOUT 32
XIN1
XOUT 1
1
3
5
R 6
R 6
R 7
R 7
R 8
R 8
W AKE _UP#
0R
0R
0R
0R
DNP
DNP
DG ND
V B U
R 65
R 65
100K
100K
144
143
126
140
36
35
18
52
60
90
33
43
75
MN1B
MN1B
S AM3U
S AM3U
XIN32
XOUT 32
XIN
XOUT
G ND1
G ND2
G ND3
G ND4
G ND5
G NDB U
G NDP LL
G NDUT MI
G NDANA
1
2
1
2
1
2
B P 1
B P 1
B P 2
B P 2
B P 3
B P 3
3
4
3
4
3
4
DG ND
Evaluation Kit Hardware
12.000MHz
12.000MHz
32.768K Hz
32.768K Hz
XIN32
XOUT 32
XIN1
XOUT 1
Y 2
Y 2
Y 1
Y 1
DG ND
6478E–ATARM–30-Mar-11
3
C 25
C 25
20pF
20pF
C 27
C 27
20pF
20pF
C 24
C 24
20pF
20pF
C 26
C 26
20pF
20pF
DG ND
DG ND
4-5