ATxmega256A3 Atmel Corporation, ATxmega256A3 Datasheet - Page 240

• Manufacturer Part Number: ATxmega256A3
• Manufacturer: Atmel Corporation

Specifications of ATxmega256A3

• 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: 50
• Ext Interrupts: 50
• Usb Speed: No
• Usb Interface: No
• Spi: 10
• Twi (i2c): 2
• Uart: 7
• 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

21.4
8077H–AVR–12/09
Frame Formats
Leading edge is the first clock edge in a clock cycle. Trailing edge is the last clock edge in a
clock cycle.
Figure 21-4. UCPHA and INVEN data transfer timing diagrams.
Data transfer is frame based, where a serial frame consists of one character of data bits with
synchronization bits (start and stop bits), and an optional parity bit for error checking. Note that
this does not apply to SPI operation (See
The USART accepts all 30 combinations of the following as valid frame formats:
A frame starts with the start bit followed by the least significant data bit and all data bits ending
with the most significant bit. If enabled, the parity bit is inserted after the data bits, before the first
stop bit. One frame can be directly followed by a start bit and a new frame, or the communication
line can return to idle (high) state.
of the frame formats. Bits inside brackets are optional.
Figure 21-5. Frame Formats
• 1 start bit
• 5, 6, 7, 8, or 9 data bits
• no, even or odd parity bit
• 1 or 2 stop bits
XCK
Data setup (TXD)
Data sample (RXD)
Data setup (TXD)
Data sample (RXD)
XCK
(IDLE)
St
0
INVEN=0
1
2
Figure 21-5 on page 240
3
4
Section 21.4.2 ”SPI Frame Formats” on page
FRAME
[5]
[6]
[7]
Data setup (TXD)
Data sample (RXD)
Data setup (TXD)
Data sample (RXD)
XCK
XCK
[8]
illustrates the possible combinations
[P]
Sp1 [Sp2]
INVEN=1
(St / IDLE)
XMEGA A
241).
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