ATMEGA128RFA1-ZU Atmel, ATMEGA128RFA1-ZU Datasheet - Page 406

• Manufacturer Part Number: ATMEGA128RFA1-ZU
• Description: IC AVR MCU 2.4GHZ XCEIVER 64QFN
• Manufacturer: Atmel
• Series: ATMEGAr

Specifications of ATMEGA128RFA1-ZU

• Frequency: 2.4GHz
• Data Rate - Maximum: 2Mbps
• Modulation Or Protocol: 802.15.4 Zigbee
• Applications: General Purpose
• Power - Output: 3.5dBm
• Sensitivity: -100dBm
• Voltage - Supply: 1.8 V ~ 3.6 V
• Current - Receiving: 12.5mA
• Current - Transmitting: 14.5mA
• Data Interface: PCB, Surface Mount
• Memory Size: 128kB Flash, 4kB EEPROM, 16kB RAM
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-VFQFN, Exposed Pad
• Rf Ic Case Style: QFN
• No. Of Pins: 64
• Supply Voltage Range: 1.8V To 3.6V
• Operating Temperature Range: -40°C To +85°C
• Svhc: No SVHC (15-Dec-2010)
• Rohs Compliant: Yes
• Processor Series: ATMEGA128x
• Core: AVR8
• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 128 KB
• Data Ram Size: 16 KB
• Interface Type: JTAG
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 38
• Number Of Timers: 6
• Operating Supply Voltage: 1.8 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVR128RFA1-EK1
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

25.9.4 TWDR – TWI Data Register
25.9.5 TWAR – TWI (Slave) Address Register
406
ATmega128RFA1
In Transmit mode, TWDR contains the next byte to be transmitted. In Receive mode,
the TWDR contains the last byte received. It is writable while the TWI is not in the
process of shifting a byte. This occurs when the TWI Interrupt Flag (TWINT) is set by
hardware. Note that the Data Register cannot be initialized by the user before the first
interrupt occurs. The data in TWDR remains stable as long as TWINT is set. While data
is shifted out, data on the bus is simultaneously shifted in. TWDR always contains the
last byte present on the bus, except after a wake up from a sleep mode by the TWI
interrupt. In this case, the contents of TWDR is undefined. In the case of a lost bus
arbitration, no data is lost in the transition from Master to Slave. Handling of the ACK bit
is automatically controlled by the TWI logic. The CPU cannot access the ACK bit
directly.
• Bit 7:0 – TWD7:0 - TWI Data Register Byte
The TWAR should be loaded with the 7-bit Slave address (in the seven most significant
bits of TWAR) to which the TWI will respond when programmed as a Slave Transmitter
or Receiver. This register is not needed in the Master modes. In multi-master systems
TWAR must be set in Masters which can be addressed as Slaves by other Masters.
The LSB of TWAR is used to enable the recognition of the general call address (0x00).
There is an associated address comparator that looks for the slave address (or general
call address if enabled) in the received serial address. If a match is found, an interrupt
request is generated.
• Bit 7:1 – TWA6:0 - TWI (Slave) Address
These bits contain the TWI address operated as a Slave device.
• Bit 0 – TWGCE - TWI General Call Recognition Enable Bit
If set, this bit enables the recognition of a General Call given over the 2-wire Serial Bus.
Bit
NA ($BB)
Read/Write
Initial Value
Bit
NA ($BA)
Read/Write
Initial Value
Register Bits
TWD7
TWA6
RW
RW
7
1
7
0
TWD6
TWA5
RW
RW
6
1
6
0
TWD5
TWA4
RW
RW
5
1
5
0
Value
0x01
0x02
0x03
TWD4
TWA3
RW
RW
4
1
4
0
Description
4
16
64
TWD3
TWA2
RW
RW
3
1
3
0
TWD2
TWA1
RW
RW
2
1
2
0
TWD1
TWA0
RW
RW
1
1
1
0
8266B-MCU Wireless-03/11
TWGCE
TWD0
RW
RW
0
1
0
0
TWDR
TWAR