PLC remote debugger development using GDB

This paper presents the implementation of a debugger for a PLC with an in-house embedded processor by using GDB. Since GDB consists of target-independent and target dependent parts, we can reduce the amount of work required to implement a debugger by using the machine-independent part of GDB. Because remote serial protocol (RSP) used in communication with a target board in GDB is different from our PLC protocol, we design a protocol translator which translates RSP into our PLC protocol. The protocol translator also changes the response of the target into form of RSP. Since the stack management scheme depends on the target compiler, we also add new stack management routines.