1 files changed, 5 insertions, 6 deletions
diff --git a/sw/eval-clock-cw-tx/src/usb.rs b/sw/eval-clock-cw-tx/src/usb.rs
index 941a024..e803c91 100644
--- a/sw/eval-clock-cw-tx/src/usb.rs
+++ b/sw/eval-clock-cw-tx/src/usb.rs
@@ -1,4 +1,4 @@
-
+use core::fmt::Write;
 use stm32f1xx_hal::gpio;
 use stm32f1xx_hal::pac;
 use stm32f1xx_hal::pac::{interrupt, Interrupt};
@@ -74,17 +74,16 @@ fn usb_interrupt() {
     }
 
     let mut buf = [0u8; 8];
+    let mut string = arrayvec::ArrayString::<[_; 16]>::new();
 
     match serial.read(&mut buf) {
         Ok(count) if count > 0 => {
             // Echo back in upper case
             for c in buf[0..count].iter_mut() {
-                if 0x61 <= *c && *c <= 0x7a {
-                    *c &= !0x20;
-                }
+                write!(string, "{:02x}", *c).ok();
             }
-
-            serial.write(&buf[0..count]).ok();
+            serial.write(string.as_bytes()).ok();
+            string.clear();
         }
         _ => {}
     }