debugWIRE

debugWIRE was developed as a cheaper alternative to JTAG , especially for processors with limited resources. It is supported by most modern 8-bit AVR controllers. The user is able to read and write all the memory areas ( FLASH , EEPROM , Fuse bits) and control over the execution of the program inside the controller ( backup points in the program memory). However, the protocol does not support step- by -step execution .

The protocol uses a single bidirectional reset line for data entry and exit.

Software breakpoints are generated using the Break command in the AVR command system . The integrated development environment ensures the preservation of the original command, replaced by Break in the memory of the desktop computer, with its subsequent restoration and continuation of the execution of the program. Thus, the use of software breakpoints spends a limited resource of microcontroller data — the maximum possible number of write cycles to erase program memory. You need to make sure that the debugger does not consume it completely.

Since the external reset input RESET is used for debugging, it becomes impossible to check the external reset circuits.

At the time of stopping the processor, in order not to disrupt the operation of the system, care must be taken when accessing the I / O registers via the debugger.

In debug mode, the power consumed by the processor increases, so you should not forget to switch the DWEN fuse switch back to its initial state after debugging.

• ATmega48 / V ATmega88 / V ATmega168 / V ^[1]
• ATmega48A / PA / 88A / PA / 168A / PA / 328 / P ^[2]
• ATtiny13 / V ^[3]
• ATtiny1634 ^[4]
• ATtiny2313 / V ^[5]
• ATtiny24 / ATtiny44 / ATtiny84 ^[6]
• ATtiny24A / ATtiny44A / ATtiny84A ^[7]
• ATtiny25 / V / ATtiny45 / V / ATtiny85 / V ^[8]
• ATtiny261 / V ATtiny461 / V ATtiny861 / V ^[9]

• A.V. Belov. 6.14. Built-in debugWIRE debugging system // Self-Teacher device developer on AVR microcontrollers. - SPb. : Science and Technology, 2008. - p. 508-517. - 544 s. - ("Ham Radio"). - ISBN 978-5-94387-363-8 .

• Debug AVR applications using JTAG or debugWIRE interface