fix!: don't require defmt always

.cargo/config.toml

@@ -4,8 +4,6 @@ target = "thumbv6m-none-eabi"
 [target.thumbv6m-none-eabi]
 runner = 'probe-rs run --chip STM32L053R8'
 
-rustflags = ["-C", "link-arg=-Tlink.x", "-C", "link-arg=-Tdefmt.x"]
-
 
 [alias]
 cflash = "flash --chip STM32L053R8"

Cargo.toml

@@ -14,6 +14,29 @@ cortex-m-rt = "0.7.5"
 panic-halt = "1.0.0"
 hd44780-driver = "0.4.0"
 heapless = "0.8.0"
-defmt = "1.0.1"
-defmt-rtt = "1.0.0"
-panic-probe = { version = "0.3", features = ["print-defmt"] }
+defmt = {version="1.0.1", optional= true}
+defmt-rtt = {version="1.0.0", optional=true}
+panic-probe = { version = "0.3", features = ["print-defmt"], optional=true }
+
+[features]
+logging = ["dep:defmt", "dep:defmt-rtt", "dep:panic-probe"]
+
+[[example]]
+name = "logging"
+path = "examples/logging.rs"
+required-features = ["logging"]
+
+[[example]]
+name = "rtc-log"
+path = "examples/rtc-log.rs"
+required-features = ["logging"]
+
+[[example]]
+name = "temperature"
+path = "examples/temperature.rs"
+required-features = ["logging"]
+
+[[example]]
+name = "aes_ecb"
+path = "examples/aes_ecb.rs"
+required-features = ["logging"]

build.rs

@@ -0,0 +1,8 @@
+fn main() {
+    println!("cargo::rerun-if-changed=Cargo.toml");
+    println!("cargo::rustc-link-arg=-Tlink.x");
+    #[cfg(feature = "logging")]
+    {
+        println!("cargo::rustc-link-arg=-Tdefmt.x");
+    }
+}