ATSAM3X-EK Atmel, ATSAM3X-EK Datasheet - Page 12

• Manufacturer Part Number: ATSAM3X-EK
• Description: Development Boards & Kits - ARM EVAL KIT SAM3X & SAM3A series
• Manufacturer: Atmel

Specifications of ATSAM3X-EK

• Rohs: yes
• Product: Evaluation Kits
• Tool Is For Evaluation Of: SAM3X
• Core: ARM Cortex M3
• Interface Type: Serial
• Operating Supply Voltage: 3.3 V
• Factory Pack Quantity: 1

11156A–ATARM–25-May-12
4.3.3
4.3.4
4-4
Clock Circuitry
Reset and Wake-Up Circuitry
The chip select signals SDCS and NCS0 are used for SDRAM and NAND-Flash chips selection, respec-
tively. Furthermore, a dedicated jumper can disconnect these from the memories, to let SDCS and
NCS0 be used for other custom purpose.
The clock generator of a SAM3X8H microcontroller is made up of:
The SAM3X-EK board is equipped with one 12 MHz crystal, one 32,768 Hz crystal.
Figure 4-4.
The on-board NRST button BP1 and NRSTB button BP2 provide the SAM3X8H 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 and can be driven low to pro-
vide a reset signal to the external components, or asserted low externally to reset the microcontroller. It
will reset the Core and the peripherals except the Backup region (RTC, RTT and Supply Controller).
There is no constraint on the length of the reset pulse, in any case the reset controller guarantee a mini-
mum pulse length. The NRST pin integrates a permanent pull-up resistor to VDDIO of about 100 k?.
On the SAM3X-EK board, the NRST signal is connected to the LCD module, JTAG port and Ethernet
Physical Transceiver.
The NRSTB pin is input only and enables asynchronous reset of the SAM3X/A series when asserted
low. The NRSTB pin integrates a permanent pull-up resistor of about 15 kOhms. This allows connection
A Low Power 32,768 Hz Slow Clock Oscillator with bypass mode
A 3 to 20 MHz Crystal Oscillator, which can be bypassed (12 MHz needed in case of USB)
High precision 8/12 MHz factory trimmed internal RC oscillator with 4 MHz Default Frequency for fast
device startup
A 480 MHz UTMI PLL providing a clock for the USB High Speed Controller
A 96 to 192 MHz programmable PLL (input from 8 to 16 MHz), capable of providing the clock MCK to
the processor and to the peripherals.
External Clock Source
System Buttons
32.768KHz
32.768KHz
WAKE UP
12MHz
12MHz
Y2
Y2
NRST
NRSTB
Y1
Y1
C33
C33
C36
C36
C40
C40
C42
C42
10pF
10pF
10pF
10pF
20pF
20pF
20pF
20pF
1
2
1
2
1
2
BP1
BP1
BP2
BP2
BP3
BP3
3
4
3
4
3
4
P1
P2
U5
U6
C22
C22
XIN
XOUT
XIN32
XOUT32
R23
R23
10nF
10nF
100K
100K
NRST [3,5,7]
NRSTB [3]
FWUP [3]
VDDBU [3]
VDDBU [3]
SAM3X-EK User Guide