ATxmega128B1 Atmel Corporation, ATxmega128B1 Datasheet - Page 337

• 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

25.15.3
8291A–AVR–10/11
REFCTRL – Reference Control register
Table 25-1.
• Bit 4 – CONVMODE: Conversion Mode
This bit controls whether the ADC will work in signed or unsigned mode. By default, this bit is
cleared and the ADC is configured for unsigned mode. When this bit is set, the ADC is config-
ured for signed mode.
• Bit 3 – FREERUN: Free Running Mode
This bit controls the free running mode for the ADC. Once a conversion is finished, the next input
will be sampled and converted.
• Bit 2:1 – RESOLUTION[1:0]: Conversion Result Resolution
These bits define whether the ADC completes the conversion at 12- or 8-bit result resolution.
They also define whether the 12-bit result is left or right adjusted within the 16-bit result regis-
ters. See
Table 25-2.
• Bit 0 – Reserved
This bit is unused and reserved for future use. For compatibility with future devices, always write
this bit to zero when this register is written.
• Bit 7 – Reserved
This bit is unused and reserved for future use. For compatibility with future devices, always write
this bit to zero when this register is written.
Bit
+0x02
Read/Write
Initial Value
RESOLUTION[1:0]
CURRLIMIT[1:0]
Table 25-2 on page 337
00
01
10
11
00
01
10
11
R
7
–
0
ADC current limitations.
ADC conversion result resolution.
R/W
6
0
Group Configuration
NO
LOW
MED
HIGH
Group Configuration
12BIT
8BIT
LEFT12BIT
REFSEL[2:0]
R/W
5
0
for possible settings.
R/W
4
0
Description
No limit
Low current limit, max. sampling rate 225kSPS
Medium current limit, max. sampling rate 150kSPS
High current limit, max. sampling rate 75kSPS
12-bit result, right adjusted
Reserved
8-bit result, right adjusted
12-bit result, left adjusted
Description
R
3
–
0
Atmel AVR XMEGA B
R
2
–
0
BANDGAP
R/W
1
0
TEMPREF
R/W
0
0
REFCTRL
337