ATxmega128B1 Atmel Corporation, ATxmega128B1 Datasheet - Page 157

• Manufacturer Part Number: ATxmega128B1
• Manufacturer: Atmel Corporation

Specifications of ATxmega128B1

• 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: 53
• Ext Interrupts: 53
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 3
• Twi (i2c): 1
• Uart: 2
• Segment Lcd: 160
• 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
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 8
• Eeprom (bytes): 2048
• 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: 3
• Output Compare Channels: 10
• Input Capture Channels: 10
• Pwm Channels: 10
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

13.7
8291A–AVR–10/11
Capture Channel
A counter wraparound can occur in any mode of operation when up-counting without buffering,
as shown in
and if a new TOP value that is lower than current CNT is written to PER, it will wrap before a
compare match happen.
Figure 13-8. Unbuffered dual-slope operation.
When double buffering is used, the buffer can be written at any time and still maintain correct
operation. The period register is always updated on the UPDATE condition, as shown for dual-
slope operation in
Figure 13-9. Changing the period using buffering.
The CC channels can be used as capture channels to capture external events and give them a
timestamp. To use capture, the counter must be set for normal operation.
Events are used to trigger the capture; i.e., any events from the event system, including pin
change from any pin, can trigger a capture operation. The event source select setting selects
which event channel will trigger CC channel A. The subsequent event channels then trigger
events on subsequent CC channels, if configured. For example, setting the event source select
to event channel 2 results in CC channel A being triggered by event channel 2, CC channel B
triggered by event channel 3, and so on.
CNT
CNT
BOTTOM
MAX
Figure
BOTTOM
MAX
Figure
13-8. This due to the fact that CNT and PER are continuously compared,
PERBUF that is higher
New TOP written to
New Period written to
PER that is higher
than current CNT
than current CNT
13-9. This prevents wraparound and the generation of odd waveforms.
Counter Wraparound
New Period written to
PERBUF that is lower
New TOP written to
than current CNT
PER that is lower
than current CNT
Atmel AVR XMEGA B
New PER is updated
with PERBUF value.
"update"
"write"
"update"
"write"
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