ATxmega256A3BU Atmel Corporation, ATxmega256A3BU Datasheet - Page 141

• 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

13.3.1
13.3.1.1
8331A–AVR–07/11
Totem-pole
Totem-pole with Pull-down
The pin n configuration (PINnCTRL) register is used for additional I/O pin configuration. A pin
can be set in a totem-pole, wired-AND, or wired-OR configuration. It is also possible to enable
inverted input and output for a pin.
A totem-pole output has four possible pull configurations: totem-pole (push-pull), pull-down, pull-
up, and bus-keeper. The bus-keeper is active in both directions. This is to avoid oscillation when
disabling the output. The totem-pole configurations with pull-up and pull-down have active resis-
tors only when the pin is set as input. This feature eliminates unnecessary power consumption.
For wired-AND and wired-OR configuration, the optional pull-up and pull-down resistors are
active in both input and output directions.
Since pull configuration is configured through the pin configuration register, all intermediate port
states during switching of the pin direction and pin values are avoided.
The I/O pin configurations are summarized with simplified schematics in
141
In the totem-pole (push-pull) configuration, the pin is driven low or high according to the corre-
sponding bit setting in the OUT register. In this configuration, there is no current limitation for
sink or source other than what the pin is capable of. If the pin is configured for input, the pin will
float if no external pull resistor is connected.
Figure 13-2. I/O pin configuration - Totem-pole (push-pull).
In this mode, the configuration is the same as for totem-pole mode, expect the pin is configured
with an internal pull-down resistor when set as input.
Figure 13-3. I/O pin configuration - Totem-pole with pull-down (on input).
to
Figure 13-7 on page
OUTn
OUTn
DIRn
DIRn
143.
INn
INn
Atmel AVR XMEGA AU
Pn
Pn
Figure 13-2 on page
141