ATxmega256A3 Atmel Corporation, ATxmega256A3 Datasheet - Page 245

• 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

8077H–AVR–12/09
The following equations can be used to calculate the ratio of the incoming data rate and internal
receiver baud rate.
Table 1.
Table 1.
Table 21-3
tolerated. Normal Speed mode has higher toleration of baud rate variations.
Table 21-3.
Table 21-4.
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 bit).
Samples per bit. S = 16 for Normal Speed mode and S = 8 for Double Speed mode.
First sample number used for majority voting. S
Double Speed mode.
Middle sample number used for majority voting. S
for Double Speed mode.
Is the ratio of the slowest incoming data rate that can be accepted in relation to the
receiver baud rate.
Is the ratio of the fastest incoming data rate that can be accepted in relation to the
receiver baud rate.
10
slow
D
D
5
6
7
8
9
5
6
7
and
Recommended Maximum Receiver Baud Rate Error for Normal Speed Mode
(CLK2X = 0)
Recommended Maximum Receiver Baud Rate Error for Double Speed Mode
(CLK2X = 1)
=
Table 21-4 on page 245
------------------------------------------ -
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
)S
+
(%)
(%)
S
F
R
R
106.67
105.79
105.11
104.58
104.14
103.78
105.66
104.92
104.35
fast
fast
list the maximum receiver baud rate error that can be
(%)
(%)
Max Total Error (%)
Max Total Error (%)
+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
R
fast
F
= 8 for normal speed and S
M
=
= 9 for normal speed and S
-----------------------------------
(
D
(
+
D
1
+
)S
2
)S
+
S
Recommended Max
Recommended Max
Receiver Error (%)
Receiver Error (%)
M
XMEGA A
± 3.0
± 2.5
± 2.0
± 2.0
± 1.5
± 1.5
± 2.5
± 2.0
± 1.5
F
= 4 for
M
= 5
245