Succeeded in controlling a led with a button

.cargo/config.toml

@@ -1,12 +1,12 @@
-[target.thumbv7m-none-eabi]
+[target.thumbv7em-none-eabihf]
 # uncomment this to make `cargo run` execute programs on QEMU
 # runner = "qemu-system-arm -cpu cortex-m3 -machine lm3s6965evb -nographic -semihosting-config enable=on,target=native -kernel"
 
 [target.'cfg(all(target_arch = "arm", target_os = "none"))']
 # uncomment ONE of these three option to make `cargo run` start a GDB session
 # which option to pick depends on your system
 # runner = "arm-none-eabi-gdb -q -x openocd.gdb"
-# runner = "gdb-multiarch -q -x openocd.gdb"
+runner = "gdb-multiarch -q -x openocd.gdb"
 # runner = "gdb -q -x openocd.gdb"
 
 rustflags = [
@@ -29,9 +29,9 @@ rustflags = [
 [build]
 # Pick ONE of these default compilation targets
 # target = "thumbv6m-none-eabi"        # Cortex-M0 and Cortex-M0+
-target = "thumbv7m-none-eabi"        # Cortex-M3
+# target = "thumbv7m-none-eabi"        # Cortex-M3
 # target = "thumbv7em-none-eabi"       # Cortex-M4 and Cortex-M7 (no FPU)
-# target = "thumbv7em-none-eabihf"     # Cortex-M4F and Cortex-M7F (with FPU)
+target = "thumbv7em-none-eabihf"     # Cortex-M4F and Cortex-M7F (with FPU)
 # target = "thumbv8m.base-none-eabi"   # Cortex-M23
 # target = "thumbv8m.main-none-eabi"   # Cortex-M33 (no FPU)
 # target = "thumbv8m.main-none-eabihf" # Cortex-M33 (with FPU)