28.3
28.4
28.5
28.6
28.7
28.8
Data Registers ...............................................................................................303
Boundary-scan Specific JTAG Instructions ...................................................305
Boundary-scan Chain ....................................................................................306
Boundary-scan Related Register in I/O Memory ...........................................309
ATmega640/1280/1281/2560/2561 Boundary-scan Order ............................309
Boundary-scan Description Language Files ..................................................309
29 Boot Loader Support – Read-While-Write Self-Programming ......... 318
29.1
29.2
29.3
29.4
29.5
29.6
29.7
Features ........................................................................................................318
Application and Boot Loader Flash Sections .................................................318
Read-While-Write and No Read-While-Write Flash Sections ........................318
Boot Loader Lock Bits ...................................................................................321
Addressing the Flash During Self-Programming ...........................................323
Self-Programming the Flash ..........................................................................324
Register Description ......................................................................................334
30 Memory Programming ......................................................................... 337
30.1
30.2
30.3
30.4
30.5
30.6
30.7
30.8
30.9
Program And Data Memory Lock Bits ...........................................................337
Fuse Bits ........................................................................................................338
Signature Bytes .............................................................................................340
Calibration Byte .............................................................................................340
Page Size ......................................................................................................340
Parallel Programming Parameters, Pin Mapping, and Commands ...............340
Parallel Programming ....................................................................................343
Serial Downloading ........................................................................................351
Programming via the JTAG Interface ............................................................357
31 Electrical Characteristics .................................................................... 370
31.1
31.2
31.3
31.4
31.5
31.6
31.7
31.8
31.9
DC Characteristics .........................................................................................370
Speed Grades ...............................................................................................372
Clock Characteristics .....................................................................................374
External Clock Drive ......................................................................................374
System and Reset Characteristics ................................................................375
2-wire Serial Interface Characteristics ...........................................................375
SPI Timing Characteristics ............................................................................377
ADC Characteristics – Preliminary Data ........................................................379
External Data Memory Timing .......................................................................381
32 Typical Characteristics ........................................................................ 387
vi
ATmega640/1280/1281/2560/2561
2549L–AVR–08/07
ATMEL [ ATMEL ]
