260
ATmega165A/PA/325A/PA/3250A/PA/645A/P/6450A/P [DATASHEET]
8285E–AVR–02/2013
27.3
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.
27.4
Calibration Byte
The Atmel ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/6450A/6450P 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.
27.5
Page Size
27.6
Parallel Programming Parameters, Pin Mapping, and Commands
This section describes how to parallel program and verify Flash Program memory, EEPROM Data memory, Mem-
ory Lock bits, and Fuse bits in the ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/6450A/6450P.
Pulses are assumed to be at least 250ns unless otherwise noted.
27.6.1
Signal names
In this sect io n, som e pins of the A tm el
ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/6450A/6450P are referenced by signal names
Table 27-6.
Device and JTAG ID.
Part
Signature bytes
JTAG
0x000
0x001
0x002
Part number
Manufacture ID
ATmega165A
0x1E
0x94
0x10
9407
0x1F
ATmega165PA
0x1E
0x94
0x07
9407
0x1F
ATmega325A
0x1E
0x95
0x05
950D
0x1F
ATmega325PA
0x1E
0x95
0x0D
950D
0x1F
ATmega3250A
0x1E
0x95
0x06
950E
0x1F
ATmega3250PA
0x1E
0x95
0x0E
950E
0x1F
ATmega645A
0x1E
0x96
0x05
960D
0x1F
ATmega645P
0x1E
0x96
0x0D
960D
0x1F
ATmega6450A
0x1E
0x96
0x06
960E
0x1F
ATmega6450P
0x1E
0x96
0x0E
960E
0x1F
Table 27-7.
No. of words in a page and no. of pages in the Flash.
Flash size
Page size
PCWORD
No. of pages
PCPAGE
PCMSB
8K words (16Kbytes)
64 words
PC[5:0]
128
PC[12:6]
12
Table 27-8.
No. of words in a page and no. of pages in the EEPROM.
EEPROM size
Page size
PCWORD
No. of pages
PCPAGE
EEAMSB
512bytes
4 bytes
EEA[1:0]
128
EEA[8:2]
8