Datasheet

Table Of Contents
328
ATmega640/V-1280/V-1281/V-2560/V-2561/V [DATASHEET]
2549Q–AVR–02/2014
30.3 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 ATmega640/1280/1281/2560/2561 the signature bytes are given in Table 30-6.
30.4 Calibration Byte
The ATmega640/1280/1281/2560/2561 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.
30.5 Page Size
30.6 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 ATmega640/1280/1281/2560/2561. Pulses are assumed to be at least 250ns
unless otherwise noted.
30.6.1 Signal Names
In this section, some pins of the ATmega640/1280/1281/2560/2561 are referenced by signal names describing
their functionality during parallel programming, see Figure 30-1 and Table 30-9 on page 329. Pins not described in
the following table are referenced by pin names.
The XA1/XA0 pins determine the action executed when the XTAL1 pin is given a positive pulse. The bit coding is
shown in Table 30-12 on page 330.
W hen pulsing WR
or OE, the command loaded determines the action executed. The different commands are
shown in Table 30-13 on page 330.
Table 30-6. Device and JTAG ID
Part
Signature Bytes Address JTAG
0x000 0x001 0x002 Part Number Manufacture ID
ATmega640 0x1E 0x96 0x08 9608 0x1F
ATmega1280 0x1E 0x97 0x03 9703 0x1F
ATmega1281 0x1E 0x97 0x04 9704 0x1F
ATmega2560 0x1E 0x98 0x01 9801 0x1F
ATmega2561 0x1E 0x98 0x02 9802 0x1F
Table 30-7. No. of Words in a Page and No. of Pages in the Flash
Flash Size Page Size PCWORD No. of Pages PCPAGE PCMSB
128K words (256Kbytes) 128 words PC[6:0] 1024 PC[16:7] 16
Table 30-8. No. of Words in a Page and No. of Pages in the EEPROM
EEPROM Size Page Size PCWORD No. of Pages PCPAGE EEAMSB
4Kbytes 8 bytes EEA[2:0] 512 EEA[11:3] 11