ATxmega128A1 Atmel Corporation, ATxmega128A1 Datasheet - Page 133

• 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

13.4.4
13.5
8077H–AVR–12/09
Reading the Pin value
Wired-AND
Figure 13-6. Output configuration - Wired-OR with optional pull-down.
With Wired-AND configuration, the pin will be driven low when the corresponding bit in OUT is
written to zero. When OUT is set to one, the pin is released allowing the pin to be pulled low with
the internal or an external pull-resistor. If internal pull-up is used, this is also active if the pin is
set as input.
Figure 13-7. Output configuration - Wired-AND with optional pull-up.
Independent of the pin data direction, the pin value can be read from the IN register as shown in
Figure 13-1 on page
register bit and the preceding flip-flop constitute a synchronizer. The synchronizer is needed to
avoid metastability if the physical pin changes value near the edge of the internal clock. The
Synchronizer introduces a delay on the internal signal line.
timing diagram of the synchronization when reading an externally applied pin value. The maxi-
mum and minimum propagation delays are denoted t
130. If the digital input is disabled, the pin value cannot be read. The IN
OUTn
OUTn
INn
INn
pd,max
and t
Figure 13-8 on page 134
pd,min
respectively.
Pn
Pn
XMEGA A
shows a
133