ATxmega256A3BU Atmel Corporation, ATxmega256A3BU Datasheet - Page 113

• Manufacturer Part Number: ATxmega256A3BU
• Manufacturer: Atmel Corporation

Specifications of ATxmega256A3BU

• Flash (kbytes): 256 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 47
• Ext Interrupts: 49
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 8
• Twi (i2c): 2
• Uart: 6
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 16
• Adc Resolution (bits): 12
• Adc Speed (ksps): 2000
• Analog Comparators: 4
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 16
• Eeprom (bytes): 4096
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.6 to 3.6
• Operating Voltage (vcc): 1.6 to 3.6
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 7
• Output Compare Channels: 22
• Input Capture Channels: 22
• Pwm Channels: 22
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

9.3.2
9.4
9.4.1
9.4.2
8331A–AVR–07/11
Reset Sources
Oscillator Startup
Power-on Reset
Brownout Detection
Whenever a reset occurs, the clock system is reset and the internal 2MHz internal oscillator is
chosen as the source for Clk
After the reset delay, the 2MHz internal oscillator clock is started, and its calibration values are
automatically loaded from the calibration row to the calibration registers.
A power-on reset (POR) is generated by an on-chip detection circuit. The POR is activated when
the V
sequence.
The POR is also activated to power down the device properly when the V
below the V
The V
teristics data.
Figure 9-2.
Figure 9-3.
The on-chip brownout detection (BOD) circuit monitors the V
paring it to a fixed, programmable level that is selected by the BODLEVEL fuses. If disabled,
BOD is forced on at the lowest level during chip erase and when the PDI is enabled.
INTERNAL
INTERNAL
TIME-OUT
TIME-OUT
CC
POT
RESET
RESET
RESET
RESET
rises and reaches the POR threshold voltage (V
level is higher for falling V
V
V
CC
CC
POT
MCU startup, RESET tied to V
MCU startup, RESET extended externally,
level.
V
V
V
SYS
POT
POT
RST
.
t
TOUT
CC
than for rising V
CC
V
.
RST
t
TOUT
Atmel AVR XMEGA AU
CC
. Consult the datasheet for POR charac-
POT
CC
), and this will start the reset
level during operation by com-
CC
falls and drops
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