ATxmega128A1 Atmel Corporation, ATxmega128A1 Datasheet - Page 131

• Manufacturer Part Number: ATxmega128A1
• Manufacturer: Atmel Corporation

Specifications of ATxmega128A1

• Flash (kbytes): 128 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 78
• Ext Interrupts: 78
• Usb Speed: No
• Usb Interface: No
• Spi: 12
• Twi (i2c): 4
• Uart: 8
• 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: 4
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 8
• Eeprom (bytes): 2048
• Self Program Memory: YES
• External Bus Interface: 1
• Dram Memory: sdram
• 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: 8
• Output Compare Channels: 24
• Input Capture Channels: 24
• Pwm Channels: 24
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

13.4
13.4.1
13.4.1.1
8077H–AVR–12/09
I/O Pin Configuration
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 the pin.
For totem-pole output there are 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 oscil-
lation when disabling the output. The totem-pole configurations with pull-up and pull-down only
have active resistors 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 direction.
Since pull configuration is configured through the pin configuration register, all intermediate port
states during switching of pin direction and pin values are avoided.
The I/O pin configurations are summarized with simplified schematics from
131
When configured for Totem-pole (push-pull), the pin is driven low or high according to the corre-
sponding bit setting in OUT. 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 exter-
nal pull is connected.
Figure 13-2. I/O pin configuration - Totem-pole (push-pull)
In this mode, the configuration is as for Totem-pole, expect the pin is configured with internal
pull-down 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
DIRn
133.
INn
OUTn
DIRn
INn
Pn
Figure 13-2 on page
XMEGA A
Pn
131