WIP, sd fails to init

src/utils.rs

@@ -0,0 +1,11 @@
+#[macro_export]
+macro_rules! format {
+    ($len:literal, $($arg:tt)*) => {{
+        use heapless::String;
+        use core::fmt::Write;
+
+        let mut s: String<$len> = String::new();
+        let _ = write!(&mut s, $($arg)*);
+        s
+    }}
+}