ATxmega256A3BU Atmel Corporation, ATxmega256A3BU Datasheet - Page 93

• Manufacturer Part Number: ATxmega256A3BU
• Manufacturer: Atmel Corporation

Specifications of ATxmega256A3BU

• 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: 47
• Ext Interrupts: 49
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 8
• Twi (i2c): 2
• Uart: 6
• 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

7.9.5
8331A–AVR–07/11
USBSCTRL – USB Control Register
• Bit 0 – RTCEN: RTC Clock Source Enable
Setting the RTCEN bit enables the selected RTC clock source for the real-time counter.
• Bit 7:6 – Reserved
These bits are unused and reserved for future use. For compatibility with future devices, always
write these bits to zero when this register is written.
• Bit 5:3 – USBPSDIV[2:0]: USB Prescaler Division Factor
These bits define the division ratio of the USB clock prescaler according to
93. These bits are locked as long as the USB clock source is enabled.
Table 7-5.
• Bit 2:1 – USBSRC[1:0]: USB Clock Source
These bits select the clock source for the USB module according to
Table 7-6.
Note:
• Bit 0 – USBSEN: USB Clock Source Enable
Setting this bit enables the selected clock source for the USB device module.
Bit
+0x04
Read/Write
Initial Value
USBPSDIV[2:0]
USBSRC[1:0]
1. The 32MHz internal oscillator must be calibrated to 48MHz before selecting this as source for
000
001
010
011
100
101
110
111
00
01
the USB device module. Refer to
R
7
–
0
USB prescaler division factor.
USB clock source.
Group Configuration
Group Configuration
6
–
R
0
RC32M
PLL
16
32
—
—
1
2
4
8
R/W
5
0
USBPSDIV[2:0]
R/W
”DFLL 2MHz and DFLL 32MHz” on page
4
0
Description
No division
Divide by 2
Divide by 4
Divide by 8
Divide by 16
Divide by 32
Reserved
Reserved
Description
PLL
32MHz internal oscillator
R/W
3
0
Atmel AVR XMEGA AU
R/W
2
0
USBSRC[1:0]
(1)
Table 7-6 on page
R/W
1
0
Table 7-5 on page
USBSEN
87.
R/W
0
0
USBSCTRL
93.
93