ATSAM3X4EA-AU Atmel, ATSAM3X4EA-AU Datasheet - Page 537

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ATSAM3X4EA-AU

Manufacturer Part Number
ATSAM3X4EA-AU
Description
ARM Microcontrollers - MCU QFP144,GREEN, IND TEMP, MRL A
Manufacturer
Atmel
Datasheet

Specifications of ATSAM3X4EA-AU

Rohs
yes
Core
ARM Cortex M3
Processor Series
SAM3X
Data Bus Width
32 bit
Maximum Clock Frequency
84 MHz
Program Memory Size
256 KB
Data Ram Size
64 KB
On-chip Adc
Yes
Operating Supply Voltage
2.4 V to 3.6 V
Operating Temperature Range
- 40 C to +85 C
Package / Case
LQFP-144
Mounting Style
SMD/SMT
Factory Pack Quantity
60

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATSAM3X4EA-AU
Manufacturer:
Atmel
Quantity:
10 000
29.1.4.1
29.1.4.2
11057B–ATARM–28-May-12
11057B–ATARM–28-May-12
Slow Clock RC Oscillator
Slow Clock Crystal Oscillator
By default, the Slow Clock RC Oscillator is enabled and selected. The user has to take into
account the possible drifts of the RC Oscillator. More details are given in the section “DC Char-
acteristics” of the product datasheet.
It can be disabled via the XTALSEL bit in the Supply Controller Control Register (SUPC_CR).
The Clock Generator integrates a 32,768 Hz low-power oscillator. In order to use this oscillator,
the XIN32 and XOUT32 pins must be connected to a 32,768 Hz crystal. Two external capacitors
must be wired as shown in
tics” of the product datasheet.
Note that the user is not obliged to use the Slow Clock Crystal and can use the RC oscillator
instead.
Figure 29-2. Typical Slow Clock Crystal Oscillator Connection
The user can select the crystal oscillator to be the source of the slow clock, as it provides a more
accurate frequency. The command is made by writing the Supply Controller Control Register
(SUPC_CR) with the XTALSEL bit at 1. This results in a sequence which enables the crystal
oscillator and then disables the RC oscillator to save power. The switch of the slow clock source
is glitch free. The OSCSEL bit of the Supply Controller Status Register (SUPC_SR) tracks the
oscillator frequency downstream. It must be read in order to be informed when the switch
sequence, initiated when a new value is written in MOSCSEL bit of CKGR_MOR, is done.
Coming back on the RC oscillator is only possible by shutting down the VDDBU power supply. If
the user does not need the crystal oscillator, the XIN32 and XOUT32 pins can be left
unconnected.
The user can also set the crystal oscillator in bypass mode instead of connecting a crystal. In
this case, the user has to provide the external clock signal on XIN32. The input characteristics of
the XIN32 pin are given in the product electrical characteristics section. In order to set the
bypass mode, the OSCBYPASS bit of the Supply Controller Mode Register (SUPC_MR) needs
to be set at 1.
The user can set the Slow Clock Crystal Oscillator in bypass mode instead of connecting a crys-
tal. In this case, the user has to provide the external clock signal on XIN32. The input
characteristics of the XIN32 pin under these conditions are given in the product electrical char-
acteristics section.
The programmer has to be sure to set the OSCBYPASS bit in the Supply Controller Mode Reg-
ister (SUPC_MR) and XTALSEL bit in the Supply Controller Control Register (SUPC_CR).
Figure
XIN32
29-2. More details are given in the section “DC Characteris-
32,768 Hz
Crystal
XOUT32
GND
SAM3X/A
SAM3X/A
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