ATxmega64A1 Atmel Corporation, ATxmega64A1 Datasheet - Page 91

• Manufacturer Part Number: ATxmega64A1
• Manufacturer: Atmel Corporation

Specifications of ATxmega64A1

• Flash (kbytes): 64 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: 78
• Ext Interrupts: 78
• Usb Speed: No
• Usb Interface: No
• Spi: 12
• Twi (i2c): 4
• Uart: 8
• 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: 4
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 4
• Eeprom (bytes): 2048
• Self Program Memory: YES
• External Bus Interface: 1
• Dram Memory: sdram
• 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: 8
• Output Compare Channels: 24
• Input Capture Channels: 24
• Pwm Channels: 24
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

8067M–AVR–09/10
1. Bandgap voltage input for the ACs cannot be changed when used for both ACs
2. VCC voltage scaler for AC is non-linear
Figure 35-1. Analog Comparator Voltage Scaler vs. Scalefac
3. The ADC has up to ±2 LSB inaccuracy
4. ADC gain stage output range is limited to 2.4 V
simultaneously
If the Bandgap voltage is selected as input for one Analog Comparator (AC) and then
selected/deselected as input for another AC, the first comparator will be affected for up to
1 µs and could potentially give a wrong comparison result.
Problem fix/Workaround
If the Bandgap is required for both ACs simultaneously, configure the input selection for both
ACs before enabling any of them.
The 6-bit VCC voltage scaler in the Analog Comparators is non-linear.
Problem fix/Workaround
Use external voltage input for the analog comparator if accurate voltage levels are needed
The ADC will have up to ±2 LSB inaccuracy, visible as a saw-tooth pattern on the input volt-
age/ output value transfer function of the ADC. The inaccuracy increases with increasing
voltage reference reaching ±2 LSB with 3V reference.
Problem fix/Workaround
None, the actual ADC resolution will be reduced with up to ±2 LSB.
The amplified output of the ADC gain stage will never go above 2.4 V, hence the differential
input will only give correct output when below 2.4 V/gain. For the available gain settings, this
gives a differential input range of:
3.5
2.5
1.5
0.5
3
2
1
0
0
T = 25°C
5
10
15
20
25
SCALEFAC
30
35
40
45
50
55
XMEGA A1
60
65
3.3 V
2.7 V
1.8 V
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