213
ATmega165A/PA/325A/PA/3250A/PA/645A/P/6450A/P [DATASHEET]
8285E–AVR–02/2013
level execution of Assembly programs assembled with Atmel Corporation’s AVR Assembler and C programs com-
piled with third party vendors’ compilers.
AVR Studio runs under Microsoft Windows 95/98/2000, Windows NT and Windows XP.
For a full description of the AVR Studio, please refer to the AVR Studio User Guide. Only highlights are presented
in this document.
All necessary execution commands are available in AVR Studio, both on source level and on disassembly level.
The user can execute the program, single step through the code either by tracing into or stepping over functions,
step out of functions, place the cursor on a statement and execute until the statement is reached, stop the execu-
tion, and reset the execution target. In addition, the user can have an unlimited number of code Break Points (using
the BREAK instruction) and up to two data memory Break Points, alternatively combined as a mask (range) Break
Point.
24.7
On-chip Debug Specific JTAG Instructions
The On-chip debug support is considered being private JTAG instructions, and distributed within Atmel and to
selected third party vendors only. Instruction opcodes are listed for reference.
24.7.1
PRIVATE0; 0x8
Private JTAG instruction for accessing On-chip debug system.
24.7.2
PRIVATE1; 0x9
Private JTAG instruction for accessing On-chip debug system.
24.7.3
PRIVATE2; 0xA
Private JTAG instruction for accessing On-chip debug system.
24.7.4
PRIVATE3; 0xB
Private JTAG instruction for accessing On-chip debug system.
24.8
Using the JTAG Programming Capabilities
Programming of AVR parts via JTAG is performed via the 4-pin JTAG port, TCK, TMS, TDI, and TDO. These are
the only pins that need to be controlled/observed to perform JTAG programming (in addition to power pins). It is not
required to apply 12V externally. The JTAGEN Fuse must be programmed and the JTD bit in the MCUCR Register
The JTAG programming capability supports:
Flash programming and verifying
EEPROM programming and verifying
Fuse programming and verifying
Lock bit programming and verifying
The Lock bit security is exactly as in parallel programming mode. If the Lock bits LB1 or LB2 are programmed, the
OCDEN Fuse cannot be programmed unless first doing a chip erase. This is a security feature that ensures no
back-door exists for reading out the content of a secured device.
The details on programming through the JTAG interface and programming specific JTAG instructions are given in