ATxmega16D4 Atmel Corporation, ATxmega16D4 Datasheet - Page 170
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ATxmega16D4
Manufacturer Part Number
ATxmega16D4
Description
Manufacturer
Atmel Corporation
Specifications of ATxmega16D4
Flash (kbytes)
16 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 Speed
No
Usb Interface
No
Spi
4
Twi (i2c)
2
Uart
2
Graphic Lcd
No
Video Decoder
No
Camera Interface
No
Adc Channels
12
Adc Resolution (bits)
12
Adc Speed (ksps)
200
Analog Comparators
2
Resistive Touch Screen
No
Temp. Sensor
Yes
Crypto Engine
No
Sram (kbytes)
2
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
4
Output Compare Channels
14
Input Capture Channels
14
Pwm Channels
14
32khz Rtc
Yes
Calibrated Rc Oscillator
Yes
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATxmega16D4-AU
Manufacturer:
Atmel
Quantity:
438
Part Number:
ATxmega16D4-AU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Company:
Part Number:
ATxmega16D4-MH
Manufacturer:
Atmel
Quantity:
1 605
Company:
Part Number:
ATxmega16D4-MHR
Manufacturer:
SANYO
Quantity:
50
Part Number:
ATxmega16D4-MHR
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
16.3
8210B–AVR–04/10
General TWI Bus Concepts
It is possible to disable the internal TWI drivers in the device, and enabling a 4-wire interface for
connecting external bus drivers.
The Two-Wire Interface (TWI) provides a simple two-wire bi-directional bus consisting of a serial
clock line (SCL) and a serial data line (SDA). The two lines are open collector lines (wired-AND),
and pull-up resistors (Rp) are the only external components needed to drive the bus. The pull-up
resistors will provide a high level on the lines when none of the connected devices are driving
the bus. A constant current source can be used as an alternative to the pull-up resistors.
The TWI bus is a simple and efficient method of interconnecting multiple devices on a serial bus.
A device connected to the bus can be a master or slave, where the master controls the bus and
all communication.
Figure 16-1
Figure 16-1. TWI Bus Topology
A unique address is assigned to all slave devices connected to the bus, and the master will use
this to address a slave and initiate a data transaction. 7-bit or 10-bit addressing can be used.
Several masters can be connected to the same bus, and this is called a multi-master environ-
ment. An arbitration mechanism is provided for resolving bus ownership between masters since
only one master device may own the bus at any given time.
A device can contain both master and slave logic, and can emulate multiple slave devices by
responding to more than one address.
A master indicates the start of transaction by issuing a START condition (S) on the bus. An
address packet with a slave address (ADDRESS) and an indication whether the master wishes
to read or write data (R/W), is then sent. After all data packets (DATA) are transferred, the mas-
ter issues a STOP condition (P) on the bus to end the transaction. The receiver must
acknowledge (A) or not-acknowledge (A) each byte received.
Figure 16-2
SDA
SCL
V
CC
illustrates the TWI bus topology.
shows a TWI transaction.
R
P
R
P
DEVICE #1
TWI
R
S
R
S
DEVICE #2
TWI
R
S
R
S
XMEGA D
Note: R
DEVICE #N
TWI
R
S
S
is optional
R
S
170