ATxmega256A3 Atmel Corporation, ATxmega256A3 Datasheet - Page 302

• 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

25.16 Register Description - ADC
25.16.1
25.16.2
8077H–AVR–12/09
CTRLA - ADC Control Register A
CTRLB - ADC Control Register B
• Bits 7:6 – DMASEL[1:0]: DMA Request Selection
In addition to giving DMA transfer request for each ADC channel, the ADC can be set up to give
a combined request for all channels. The combined request is decided according to the DMA-
SEL bits. See
Table 25-1.
• Bits 5:2 – CH[3:0]START: ADC Channel Start single conversion
Setting any of these bits will start a conversion on the corresponding ADC channel. Setting sev-
eral bits at the same time will start a conversion sweep on the selected ADC channels, starting
with the channel with lowest number. These bits are cleared by hardware when the conversion
has started.
• Bit 1 – FLUSH: ADC Pipeline Flush:
Setting this bit will flush the ADC pipeline. When this is done the ADC Clock will be restarted on
the next Peripheral clock edge and all conversions in progress are aborted and lost.
After the flush and the ADC Clock restart, the ADC will resume where it left off. I.e. if a channel
sweep was in progress or any conversions was pending, these will enter the ADC pipeline and
complete.
• Bit 0 – ENABLE: ADC Enable
Setting this bit enables the ADC.
• Bits 7:5 - 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
+0x01
Read/Write
Initial Value
Bit
+0x00
Read/Write
Initial Value
DMASEL[1:0]
00
01
10
11
R/W
7
R
0
-
7
0
Table 25-1
ADC DMA Request Selection
DMASEL[1:0]
R
R/W
6
0
-
6
0
for details.
Group Configuration
R
5
0
R/W
-
5
0
CH0123
CH012
CH01
CONVMODE
OFF
R/W
R/W
4
0
4
0
CH[3:0]START
FREERUN
R/W
R/W
3
0
3
0
Description
No combined DMA request
ADC Channel 0 or 1
ADC Channel 0 or 1 or 2
ADC Channel 0 or 1 or 2 or 3
R/W
R/W
RESOLUTION[1:0]
2
0
2
0
FLUSH
R/W
R/W
1
0
1
0
XMEGA A
ENABLE
R/W
R
0
0
0
0
-
CTRLA
CTRLB
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