ATxmega32A4U Atmel Corporation, ATxmega32A4U Datasheet - Page 271

• Manufacturer Part Number: ATxmega32A4U
• Manufacturer: Atmel Corporation

Specifications of ATxmega32A4U

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 34
• Ext Interrupts: 34
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 7
• Twi (i2c): 2
• Uart: 5
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 12
• Adc Speed (ksps): 2000
• Analog Comparators: 2
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 4
• Eeprom (bytes): 1024
• 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: 5
• Output Compare Channels: 16
• Input Capture Channels: 16
• Pwm Channels: 16
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

21.8
21.8.1
8331A–AVR–07/11
Register Description - TWI
CTRL – TWI Common Control Register
• Bit 7:3 – 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 2:1 – SDAHOLD[1:0]: SDA Hold Time Enable.
of SCL.
Table 21-1.
• Bit 0 – EDIEN: External Driver Interface Enable
Setting this bit enables the use of the external driver interface, and clearing this bit enables nor-
mal two-wire mode. See
Table 21-2.
Setting these bits to one enables an internal hold time on SDA with respect to the negative edge
Bit
+0x00
Read/Write
Initial Value
SDAHOLD[1:0]
EDIEN
00
01
10
11
0
1
7
–
R
0
SDA hold time.
External driver interface enable.
Mode
Normal TWI
External driver interface
Group Configuration
OFF
50NS
300NS
400NS
6
–
R
0
Table 21-2 on page 271
R
5
–
0
R
4
–
0
SDA hold time off
Comment
Four-pin interface, standard I/O, no slew rate control,
and no input filter.
Description
Typical 50ns hold time
Typical 100ns hold time
Typical 400ns hold time
Two-pin interface,slew rate control, and input filter.
for details.
Atmel AVR XMEGA AU
R
3
–
0
R/W
2
0
SDAHOLD[1:0]
R/W
1
0
EDIEN
R/W
0
0
CTRL
271