ATxmega16D4 Atmel Corporation, ATxmega16D4 Datasheet - Page 172
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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
16.3.3
16.3.4
16.3.5
16.3.6
8210B–AVR–04/10
Bit Transfer
Address Packet
Data Packet
Transaction
As illustrated by
period of the SCL line. Consequently the SDA value can only be changed during the low period
of the clock. This is ensured in hardware by the TWI module.
Figure 16-4. Data Validity
Combining bit transfers results in the formation of address and data packets. These packets
consist of 8 data bits (one byte) with the most significant bit transferred first, plus a single bit not-
acknowledge (NACK) or acknowledge (ACK) response. The addressed device signals ACK by
pulling the SCL line low, and NACK by leaving the line SCL high during the ninth clock cycle.
After the START condition, a 7-bit address followed by a read/write (R/W) bit is sent. This is
always transmitted by the Master. A slave recognizing its address will ACK the address by pull-
ing the data line low the next SCL cycle, while all other slaves should keep the TWI lines
released, and wait for the next START and address. The 7-bit address, the R/W bit and the
acknowledge bit combined is the address packet. Only one address packet for each START
condition is given, also when 10-bit addressing is used.
The R/W specifies the direction of the transaction. If the R/W bit is low, it indicates a Master
Write transaction, and the master will transmit its data after the slave has acknowledged its
address. Opposite, for a Master Read operation the slave will start to transmit data after
acknowledging its address.
Data packets succeed an address packet or another data packet. All data packets are nine bits
long, consisting of one data byte and an acknowledge bit. The direction bit in the previous
address packet determines the direction in which the data is transferred.
A transaction is the complete transfer from a START to a STOP condition, including any
Repeated START conditions in between. The TWI standard defines three fundamental transac-
tion modes: Master Write, Master Read, and combined transaction.
Figure 16-5
ing a START condition (S) followed by an address packet with direction bit set to zero
(ADDRESS+W).
SDA
SCL
illustrates the Master Write transaction. The master initiates the transaction by issu-
Figure 16-4
a bit transferred on the SDA line must be stable for the entire high
DATA
Valid
Change
Allowed
XMEGA D
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