
505
42073A-MCU Wireless-02/13
ATmega2564/1284/644RFR2
31.3 Signature Bytes
All Atmel microcontrollers have a three-byte signature code which identifies the device.
This code can be read in both serial and parallel mode, also when the device is locked.
The
three
bytes
reside
in
a
separate
address
space.
For
the
Accessing the signature bytes from software is described in section
"Reading theTable 31-6. Device and JTAG ID (48-pin package)
Part
Signature Byte Number
JTAG
0
1
2
Part Number
Manufacturer ID
ATmega2564RFR2
0x1E
0xA8
0x03
(1
0xA803
(1
0x1F
ATmega1284RFR2
0x1E
0xA7
0x03
0xA703
0x1F
ATmega644RFR2
0x1E
0xA6
0x03
0xA603
0x1F
Notes:
1. ATmega2564RFR2 revision A implements Signature Byte Number 2 = 0x02
31.4 User Signature Data
Three Flash pages are dedicated for user signature data. These signature pages are
isolated from the main Flash and will not be cleared by a Chip Erase command. Special
commands are available to erase and write data to user signature pages via the Parallel
software in the same way as the device and JTAG identifiers (see section
"Reading the31.5 Calibration Byte
The ATmega2564/1284/644RFR2 has a byte calibration value for the internal RC
Oscillator. This byte resides in the high byte of address 0x000 in the signature address
space. During reset, this byte is automatically written into the OSCCAL Register to
ensure correct frequency of the calibrated RC Oscillator.
31.6 Page Size
Table 31-7. Number of Words in a Page and Number of Pages in the Flash
Flash Size
Page Size
PCWORD
No. of
Pages
PCPAGE
PCMSB
128k words (256k bytes)
128 words
PC[6:0]
1024
PC[16:7]
16
64k words (128k bytes)
128 words
PC[6:0]
512
PC[15:7]
15
32k words (64k bytes)
128 words
PC[6:0]
256
PC[14:7]
14
Notes:
1. The page size for user signature data in all devices is also 128 words.
Table 31-8. Number of Bytes in a Page and Number of Pages in the EEPROM
EEPROM Size
Page Size
PCWORD
No. of
Pages
PCPAGE
EEAMSB
8k bytes
8 bytes
EEA[2:0]
1024
EEA[12:3]
12
4k bytes
8 bytes
EEA[2:0]
512
EEA[11:3]
11
2k bytes
8 bytes
EEA[2:0]
256
EEA[10:3]
10