How can you debug Arm-based systems with limited resources?

1 Identify the target

The first step in debugging any system is to identify the target device and its specifications, such as the Arm core, the memory layout, the peripherals, and the operating system. This will help you choose the right debugging hardware and software, such as a debugger, a probe, a serial port, or a JTAG interface. You can use tools like Arm Development Studio, Arm Keil MDK, or OpenOCD to connect to your target device and access its registers, memory, and breakpoints. You can also use commands like uname , cat /proc/cpuinfo , or readelf to get information about your target device.

2 Use printf debugging

One of the simplest and most effective ways to debug Arm-based systems with limited resources is to use printf debugging. This means inserting print statements in your code to output variables, messages, or errors to a console or a log file. You can use the standard C library function printf or the Arm-specific function ITM_SendChar to send data to a serial port or a SWO pin. You can then use a terminal emulator, such as PuTTY, Tera Term, or Minicom, to view the output on your host computer. Printf debugging can help you locate bugs, trace the execution flow, and monitor the system performance.

3 Use semihosting

Another way to debug Arm-based systems with limited resources is to use semihosting. This means using the host computer's resources, such as the file system, the screen, or the keyboard, instead of the target device's resources. You can use the Arm semihosting interface, which is a set of standard C library functions that communicate with the debugger via a breakpoint instruction. For example, you can use fopen , fwrite , or fread to access files on your host computer from your target device. Semihosting can help you reduce the memory and power consumption of your target device, as well as simplify the input and output operations.

4 Use GDB

Another way to debug Arm-based systems with limited resources is to use GDB, the GNU debugger. GDB is a powerful and versatile tool that can debug multiple languages, architectures, and platforms. You can use GDB to control the execution of your program, examine its state, modify its variables, and set breakpoints and watchpoints. You can also use GDB commands, scripts, or graphical interfaces to automate and customize your debugging process. You can use GDB with a remote target device via a serial port, a JTAG interface, or a network connection. GDB can help you debug complex and dynamic programs, as well as interact with the target device's hardware and software.

5 Use trace

Another way to debug Arm-based systems with limited resources is to use trace. Trace is a technique that records the history of the program execution, such as the instructions executed, the data accessed, or the events occurred. You can use trace to analyze the behavior, performance, and timing of your program, as well as to identify bugs, bottlenecks, and anomalies. You can use trace sources, such as the Arm CoreSight, the Arm Embedded Trace Macrocell, or the Arm Instrumentation Trace Macrocell, to generate trace data on your target device. You can then use trace tools, such as Arm Development Studio, Arm Keil MDK, or Lauterbach TRACE32, to collect, decode, and visualize the trace data on your host computer.

6 Use simulation

Another way to debug Arm-based systems with limited resources is to use simulation. Simulation is a technique that emulates the target device's hardware and software on your host computer. You can use simulation to test your program without having a physical target device, or to test scenarios that are difficult or impossible to reproduce on a real target device. You can use simulation tools, such as Arm Fast Models, Arm QEMU, or Renode, to create and run virtual models of your target device on your host computer. You can then use debugging tools, such as GDB, to debug your program on the simulated target device.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?