7
8393CS-MCU Wireless-09/14
ATmega256/128/64RFR2
3.2.22 CLKI
Input to the clock system. If selected, it provides the operating clock of the
microcontroller.
3.3 Unused Pins
Floating pins can cause power dissipation in the digital input stage. They should be
connected to an appropriate source. In normal operation modes the internal pull-up
resistors can be enabled (in Reset all GPIO are configured as input and the pull-up
resistors are still not enabled).
Bi-directional I/O pins shall not be connected to ground or power supply directly.
The digital input pins TST and CLKI must be connected. If unused pin TST can be
connected to AVSS while CLKI should be connected to DVSS.
Output pins are driven by the device and do not float. Power supply pins respective
ground supply pins are connected together internally.
XTAL1 and XTAL2 shall never be forced to supply voltage at the same time.
3.4 Configuration summary
According to the application requirements a variable memory size allows to optimize
current consumption and leakage current.
Table 3-1
Memory Configuration
Device
Flash
EEPROM
SRAM
ATmega256RFR2
256KB
8KB
32KB
ATmega128RFR2
128KB
4KB
16KB
ATmega64RFR2
64KB
2KB
8KB
Package and associated pin configuration are the same for all devices providing full
functionality to the application.
Table 3-2
System Configuration
Device
Package
GPIO
Serial IF
ADC channel
ATmega256RFR2
QFN
38
2 USART, SPI, TWI
8
ATmega128RFR2
QFN
38
2 USART, SPI, TWI
8
ATmega64RFR2
QFN
38
2 USART, SPI, TWI
8
The devices are optimized for applications based on the ZigBee and the IEEE 802.15.4
specification. Having application stack, network layer, sensor interface and an excellent
power control combined in a single chip many years of operation should be possible.
Table 3-3
Application Profile
Device
Application
ATmega256RFR2
Large Network Coordinator / Router for IEEE 802.15.4 / ZigBee Pro
ATmega128RFR2
Network Coordinator / Router for IEEE 802.15.4
ATmega64RFR2
End node device / network processor
