Rainbow Electronics ATmega128RFA1 - Manual (Page 7)

7
8266A-MCU Wireless-12/09
ATmega128RFA1
registers are unchanged as long as it fits the target application of a very small and
power efficient radio system. In addition, several new features were added.
Backward compatibility of the ATmega128RFA1 to the ATmega1281/2561 is provided
in most cases. However some incompatibilities between the microcontrollers exist.
3.3.1 Port A and Port C
Port A and Port C are not implemented. The associated registers are available but will
not provide any port control. Remaining ports are kept at their original address location
to not require changes of existing software packages.
3.3.2 External Memory Interface
The alternate pin function “External Memory interface” using Port A and Port C is not
implemented due to the missing ports.
The large internal data memory (SRAM) does not require an external memory and the
associated parallel interface. It keeps the system radiation (EMC) at a very small level
to provide very high sensitivity at the antenna input.
3.3.3 High Voltage Programming Mode
Alternate pin function BS2 (high voltage programming) of pin PA0 is mapped to a
different pin. Entering the parallel programming mode is controlled by the TST pin.
3.3.4 AVR Oscillators and External Clock
The AVR microcontroller can utilize the high performance crystal oscillator of the
2.4GHz transceiver connected to the pins XTAL1 and XTAL2. An external clock can be
applied to the microcontroller using the clock input CLKI.
3.3.5 Analog Frontend
The ATmega128RFA1 has a new A/D converter. Software compatibility is basically
assured. Nevertheless to benefit from the higher conversion speeds and the better
performance some changes are required.
4 Resources
A comprehensive set of development tools and application notes, and datasheets are
available for download on
http://www.atmel.com .
5 About Code Examples
This documentation contains simple code examples that briefly show how to use
various parts of the device. Be aware that not all C compiler vendors include bit
definitions in the header files and interrupt handling in C is compiler dependent. Please
confirm with the C compiler documentation for more details.
These code examples assume that the part specific header file is included before
compilation. For I/O registers located in extended I/O map, "IN", "OUT", "SBIS", "SBIC",
"CBI", and "SBI" instructions must be replaced with instructions that allow access to
extended I/O. Typically "LDS" and "STS" combined with "SBRS", "SBRC", "SBR", and
"CBR".
6 Data Retention
Reliability Qualification results show that the projected data retention failure rate for the
given ambient temperature is less than TBD PPM