ATXMEGA256A3B-MH Atmel, ATXMEGA256A3B-MH Datasheet - Page 79

• Manufacturer Part Number: ATXMEGA256A3B-MH
• Description: MCU AVR 256KB FLASH A3B 64-QFN
• Manufacturer: Atmel
• Series: AVR® XMEGAr

Specifications of ATXMEGA256A3B-MH

• Core Processor: AVR
• Core Size: 8/16-Bit
• Speed: 32MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Number Of I /o: 49
• Program Memory Size: 256KB (128K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 1.6 V ~ 3.6 V
• Data Converters: A/D 16x12b; D/A 2x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-MLF®, 64-QFN
• Processor Series: ATXMEGA256x
• Core: AVR8
• Data Bus Width: 8 bit, 16 bit
• Data Ram Size: 16 KB
• Interface Type: I2C, SPI, USART
• Maximum Clock Frequency: 32 MHz
• Number Of Programmable I/os: 49
• Number Of Timers: 7
• Operating Supply Voltage: 1.6 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12 bit, 8 Channel
• On-chip Dac: 12 bit, 2 Channel
• For Use With: ATAVRONEKIT - KIT AVR/AVR32 DEBUGGER/PROGRMMRATSTK600 - DEV KIT FOR AVR/AVR32770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAG770-1004 - ISP 4PORT FOR ATMEL AVR MCU SPI
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATXMEGA256A3B-MU; ATXMEGA256A3B-MU

7.4.1.4
7.4.2
7.4.2.1
7.4.2.2
7.4.2.3
8077H–AVR–12/09
External Clock Sources
2 MHz Run-time Calibrated Internal Oscillator
0.4 - 16 MHz Crystal Oscillator
External Clock Input
32.768 kHz Crystal Oscillator
This RC oscillator provides an approximate 2 MHz clock. The oscillator employs a Digital Fre-
quency Looked Loop (DFLL) that can be enabled for automatic run-time calibration of the
oscillator. A factory-calibrated value is written to the 2 MHz DFLL Calibration Register during
reset to ensure that the oscillator is running within its specification. The calibration register can
also be written from software for manual run-time calibration of the oscillator.
The XTAL1 and XTAL2 pins can be used to drive an external oscillator, either a quartz crystal or
a ceramic resonator. XTAL1 can be used as input for an external clock signal. The TOSC1 and
TOSC2 pins is dedicated for driving a 32.768 kHz crystal oscillator.
This oscillator can operate in four different modes, optimized for different frequency ranges, all
within 0.4 - 16 MHz.
Figure 7-2.
Two capacitors, C1 and C2, may be added to match the required load capacitance for the con-
nected crystal.
To drive the device from an external clock source, XTAL1 must be driven as shown in
3 on page
Figure 7-3.
A 32.768 kHz crystal oscillator can be connected between TOSC1 and TOSC2 by enabling a
dedicated Low Frequency Oscillator input circuit. A typical connection is shown in Figure
79. In this mode, XTAL2 can be used as a general I/O pin.
Crystal Oscillator Connection
External Clock Drive Configuration
Figure 7-2
P u r p o s e
E x t e r n a l
G e n e r a l
S i g n a l
C l o c k
shows a typical connection of a crystal oscillator or resonator.
I / O
C 2
C 1
X T A L 2
X T A L 1
X T A L 2
X T A L 1
G N D
XMEGA A
Figure 7-
Figure
79