ATxmega256A3U Atmel Corporation, ATxmega256A3U Datasheet - Page 235

• Manufacturer Part Number: ATxmega256A3U
• Manufacturer: Atmel Corporation

Specifications of ATxmega256A3U

• 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 Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• 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

8331A–AVR–07/11
Figure 20-4. OUT transaction state machine
The USB module then fetches the endpoint DATAPTR, and waits for a DATA0 or DATA1
packet. If a PID error or any other PID than DATA0 or DATA1 is detected, the USB module
returns to idle and waits for the next token packet.
If STALL in endpoint CTRL is set, the incoming data is discarded. If the endpoint is not isochro-
nous, a STALL handshake is returned to the host, the STALL flag in endpoint STATUS, and
STALLIF in INTFLAGSACLR/SET are set.
For isochronous endpoints, data from both a DATA0 and DATA1 packet will be accepted. For
other endpoint types, the PID is checked against TOGGLE. If they don't match, the incoming
data is discarded, and a NAK handshake is returned to the host. If BUSNACK0 is set, the incom-
ing data is discarded. The Overflow Flag (OVF) in endpoint STATUS and Overflow Interrupt Flag
(OVFIF) in INTFLAGSASET/CLR are set. If the endpoint is not isochronous, a NAK handshake
is returned to the host.
The incoming data is written to the data buffer pointed to by DATAPTR. If a bit-stuff error is
detected in the incoming data, the USB module returns to idle and waits for the next token
packet. If the number of received data bytes exceeds the maximum data payload specified by
SIZE, the remainders of the received data bytes are discarded. The packet will still be checked
for bit-stuff and CRC errors. If there was a bit-stuff or CRC error in the packet, the USB module
returns to idle and waits for the next token packet.
STATUS MANAGEMENT
ACK HANDSHAKE
CRC OK ?
No
No
No
RAM FETCH IN CONFIGURATION TABLE
RAM FETCH IN CONFIGURATION TABLE
ENDPOINT STATUS ENABLED ?
ENDPOINT FIELD =< MAXEP ?
ADDRESS MATCH OK ?
DATA : CTRL & STATUS
DATA : DATAPTR L &H
DIR : OUT ENDPOINT
DIR : OUT ENDPOINT
IDLE
Yes
Yes
Yes
OUT token
WRITE STATUS
DATA WRITE
MORE DATA ?
OK/BAD
IN RAM
Atmel AVR XMEGA AU
No
ISO
Stall & ISO
NAK HANDSHAKE
STALL HANDSHAKE
DISCARDED
WAIT DATA0/1
DATA
PID OK ?
Yes
Stall
No
No
ACK HANDSHAKE
WRITE STATUS
PID & TOGGLE
BIT STUFF OK ?
DATA WRITE
CRC OK ?
MATCH ?
OK/BAD
IN RAM
Yes
!Stall
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