Rainbow-electronics Atmega169L Manuel d'utilisateur télécharger pdf (Page 229)

229

ATmega169V/L

2514A–AVR–08/02

A list of the On-chip Debug specific JTAG instructions is given in “On-chip Debug Spe-

cific JTAG Instructions” on page 229.

The JTAGEN Fuse must be programmed to enable the JTAG Test Access Port. In addi-

tion, the OCDEN Fuse must be programmed and no Lock bits must be set for the On-

chip debug system to work. As a security feature, the On-chip debug system is disabled

when either of the LB1 or LB2 Lock bits are set. Otherwise, the On-chip debug system

would have provided a back-door into a secured device.

The AVR Studio enables the user to fully control execution of programs on an AVR

device with On-chip Debug capability, AVR In-Circuit Emulator, or the built-in AVR

Instruction Set Simulator. AVR Studio

supports source 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 and Microsoft Windows NT

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 execution,

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.

On-chip Debug Specific

JTAG Instructions

The On-chip debug support is considered being private JTAG instructions, and distrib-

uted within ATMEL and to selected third party vendors only. Instruction opcodes are

listed for reference.

PRIVATE0; 0x8 Private JTAG instruction for accessing On-chip debug system.

PRIVATE1; 0x9 Private JTAG instruction for accessing On-chip debug system.

PRIVATE2; 0xA Private JTAG instruction for accessing On-chip debug system.

PRIVATE3; 0xB Private JTAG instruction for accessing On-chip debug system.

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Rainbow-electronics Atmega169L Manuel d'utilisateur Page 229