Add a trace mode for usb tracing

meson.build

@@ -35,6 +35,15 @@ incdir = include_directories('src')
 
 subdir('src')
 
+# Build arguments
+cpp_args = ['-DPROJ_VERSION="' + meson.project_version() + '"']
+
+# USB trace mode option (for debugging without sending to hardware)
+if get_option('usb_trace_only')
+    cpp_args += ['-DUSB_TRACE_ONLY']
+    message('USB_TRACE_ONLY enabled: USB data will be logged but not sent to device')
+endif
+
 ptprnt_exe = executable(
     'ptprnt',
     'src/main.cpp',
@@ -42,7 +51,7 @@ ptprnt_exe = executable(
     dependencies: [usb_dep, log_dep, fmt_dep, pangocairo_dep, cli11_dep],
     include_directories: incdir,
     sources: [ptprnt_srcs],
-    cpp_args: ['-DPROJ_VERSION="' + meson.project_version() + '"'],
+    cpp_args: cpp_args,
 )