added onechar_itm feature for issue rust-embedded#571

cortex-m/Cargo.toml

@@ -34,6 +34,7 @@ cm7-r0p1 = ["cm7"]
 linker-plugin-lto = []
 std = []
 critical-section-single-core = ["critical-section/restore-state-bool"]
+onechar_itm = []
 
 [package.metadata.docs.rs]
 targets = [

cortex-m/src/itm.rs

@@ -73,6 +73,7 @@ impl fmt::Write for Port<'_> {
 pub struct Aligned<T: ?Sized>(pub T);
 
 /// Writes `buffer` to an ITM port.
+#[cfg(not(feature="onechar_itm"))]
 #[allow(clippy::missing_inline_in_public_items)]
 pub fn write_all(port: &mut Stim, buffer: &[u8]) {
     unsafe {
@@ -122,6 +123,24 @@ pub fn write_all(port: &mut Stim, buffer: &[u8]) {
     }
 }
 
+
+/// Writes `buffer` to an ITM port.
+/// with onechar_itm features, this write a single byte in ITM u32 register
+/// making ascii trace readable on Eclipse/STM32CubeIDE SWV monitor
+#[cfg(feature="onechar_itm")]
+#[allow(clippy::missing_inline_in_public_items)]
+pub fn write_all(port: &mut Stim, buffer: &[u8]) {
+    for c in buffer {
+        while !port.is_fifo_ready() {}
+        port.write_u8(*c);
+    }
+}
+
+
+
+
+
+
 /// Writes a 4-byte aligned `buffer` to an ITM port.
 ///
 /// # Examples

panic-itm/Cargo.toml

@@ -13,5 +13,8 @@ repository = "https://github.com/rust-embedded/cortex-m"
 version = "0.4.2"
 edition = "2018"
 
+[features]
+onechar_itm = []
+
 [dependencies]
 cortex-m = { path = "../cortex-m", version = ">= 0.5.8, < 0.8" }