This is a Pascal implementation of the debugwire protocol for small AVR controllers such as attiny85 or atmega328P. It includes a gdb remote serial protocol server so that a debugger such as gdb or LazDebuggerFpRspRemote in Lazarus can communicate with the debugwire implementation to debug on-chip code. The aim is to focus on features that would enable one to use Lazarus to both write code for and debug the generated code on compatible AVR microcontrollers.
A simple USB-serial adapter can be used to interface with hardware, see hardware documentation.
Run the dw_gdb executable and a serial port (mandatory) to connect to. It will connect to the serial port and if successfull, open a TCP port (default 1234) and wait for a TCP connection from a debugger. A baud rate can be specified for the serial connection - if not a baud rate scan will be done. The DWEN fuse can be diabled temporarily to enable ISP programming. The general syntax and command line options supported are:
dw_gdb -S <sp> [-B <bd>] [-T <tp>] [-I] [-V] [-H]
-S <sp>, -s <sp>, --serialport=<sp>
Connect to serial port <sp>, e.g. /dev/ttyUSB0
-B <bd>, -b <bd>, --baud=<bd>
Connect to serial port using baud rate <bd>. If not specified, the debugWIRE baud rate will be scanned automatically.
-T <tp>, -t <tp>, --tcpport=<tp>
Set TCP port <tp> for remote connection. If not specified, TCP port defaults to 1234.
-I, -i, --ispenable
Temporarily disable DWEN fuse to enable ISP functionality and exit.
-V, -v, --verbose
Enable verbose debug output.
-H, -h, -?, --help
Display this help and exit.Note that parameters for long options can be separated by a = or a space.
Special thanks to RikusW and others for documenting the debugwire protocol:
http://www.ruemohr.org/docs/debugwire.html
Other debugwire implementations that in some way inspired this work:
https://github.com/dcwbrown/dwire-debug
https://github.com/mvirkkunen/dwprog
https://github.com/jbtronics/WireDebugger