ATxmega256A3U Atmel Corporation, ATxmega256A3U Datasheet - Page 300

• 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
Table 23-3
tolerated. Normal speed mode has higher tolerance of baud rate variations.
Table 23-3.
Table 23-4.
The recommendations for the maximum receiver baud rate error assume that the receiver and
transmitter equally divide the maximum total error.
D
S
S
S
R
R
#(Data + Parity Bit)
#(Data + Parity Bit)
F
M
slow
fast
R
Sum of character size and parity size (D = 5 to 10 bits).
Samples per bit. S = 16 for normal speed mode and S = 8 for double speed mode.
First sample number used for majority voting. S
ble speed mode.
Middle sample number used for majority voting. S
double speed mode.
The ratio of the slowest incoming data rate that can be accepted in relation to the receiver baud
rate.
The ratio of the fastest incoming data rate that can be accepted in relation to the receiver baud
rate.
10
10
slow
D
D
5
6
7
8
9
5
6
7
8
9
and
Recommended maximum receiver baud rate error for normal speed mode
Recommended maximum receiver baud rate error for double speed mode
=
Table 23-4 on page 300
------------------------------------------ -
S 1
–
(
D
+
+
D S ⋅
R
R
slow
slow
1
93.20
94.12
94.81
95.36
95.81
96.17
94.12
94.92
95.52
96.00
96.39
96.70
)S
+
(%)
(%)
S
F
R
R
106.67
105.79
105.11
104.58
104.14
103.78
105.66
104.92
104.35
103.90
103.53
103.23
fast
fast
list the maximum receiver baud rate error that can be
(%)
(%)
Max Total Error (%)
Max Total Error (%)
F
Atmel AVR XMEGA AU
= 8 for normal speed mode and S
+6.67/-6.80
+5.79/-5.88
+5.11/-5.19
+4.58/-4.54
+4.14/-4.19
+3.78/-3.83
+5.66/-5.88
+4.92/-5.08
+4.35/-4.48
+3.90/-4.00
+3.53/-3.61
+3.23/-3.30
M
R
= 9 for normal speed mode and S
fast
=
-----------------------------------
(
D
(
+
D
1
+
)S
2
)S
+
S
Recommended Max
Recommended Max
Receiver Error (%)
Receiver Error (%)
M
± 3.0
± 2.5
± 2.0
± 2.0
± 1.5
± 1.5
± 2.5
± 2.0
± 1.5
± 1.5
± 1.5
± 1.0
F
= 4 for dou-
M
= 5 for
300