Atmel RCB256RFR2, Hardware User Manual

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Atmel AVR10004: RCB256RFR2 – Hardware User Manual [APPLICATION NOTE]
42081A
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AVR
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03/2013
11
Figure 4-3. ID EEPROM access decoding logic.
The ID EEPROM is written during board production testing with:
•
A unique serial number
•
MAC address
•
Calibration values
Calibration values are used to optimize radio transceiver performance.
Final products do not require this external ID EEPROM functionality. All data can be stored directly in the Atmel
Atmega256RFR2 internal EEPROM. The ID EEPROM is there for convenience to simplify microcontroller firmware
development. Table 4-1 shows the data structure of the ID EEPROM. The Cal RC values can be used as start values
for the RC calibration algorithm. The Cal OSC 16MHz value can simply be copied to the corresponding radio
transceiver register to reduce the frequency deviation. However, the 16MHz crystal is guaranteed to deviate less than
20ppm from the actual 16MHz value at room temperature without any calibration adjustment. When the Cal OSC
16MHz value is applied, the deviation is less than 5ppm at room temperature.
Table 4-1. ID EEPROM mapping.
Address Name Type Description
0x00 MAC address uint64 MAC address
(1)
for the 802.15.4 node, little endian byte order
0x08 Serial number uint64 Board serial number, little endian byte order
0x10 Board family uint8 Internal board family identifier
0x11 Revision uint8 Board revision number, for example 06 03 02
0x14 Feature uint8 Board features, coded into seven bits
7 Reserved
6 Reserved
5 External LNA
4 External PA
3 Reserved
2 Diversity
1 Antenna
0 SMA connector
0x15 Cal OSC 16MHz uint8 RF231 XTAL calibration value, register XTAL_TRIM
0x16 Cal RC 3.6V uint8 AVR internal RC oscillator calibration value @ 3.6V, register OSCCAL
0x17 Cal RC 2.0V uint8 AVR internal RC oscillator calibration value @ 2.0V, register OSCCAL