bare7 broken

examples/bare7.rs

 //! Serial interface loopback
 #![deny(unsafe_code)]
-#![deny(warnings)]
+//#![deny(warnings)]
 #![feature(proc_macro)]
 #![no_std]
 
 extern crate cortex_m_rtfm as rtfm;
 extern crate f4;
+extern crate heapless;
+
+#[macro_use(block)]
+extern crate nb;
+
+#[macro_use]
+extern crate cortex_m_debug;
 
 use f4::prelude::*;
 use f4::Serial;
-use f4::serial::Event;
 use f4::time::Hertz;
+use heapless::Vec;
 use rtfm::{app, Threshold};
 
 // CONFIGURATION
 const BAUD_RATE: Hertz = Hertz(115_200);
 
-// TASKS & RESOURCES
+// RTFM FRAMEWORK
 app! {
     device: f4::stm32f40x,
-
-    tasks: {
-        USART2: {
-            path: loopback,
-            resources: [USART2],
-        },
-    }
 }
+// static BUFFER: Vec<u8, [u8; 8]> = Vec::new();
 
-// INITIALIZATION PHASE
+// Init executes with interrupts disabled
+// Hence its safe to access all peripherals (no race-conditions)
+//
+// In this case init will never return
+// This is not the typical use-case as we will see later
 fn init(p: init::Peripherals) {
+    ipln!("init");
     let serial = Serial(p.USART2);
 
     serial.init(BAUD_RATE.invert(), None, p.GPIOA, p.RCC);
-    serial.listen(Event::Rxne);
+
+    let mut buffer: Vec<u8, [u8; 4]> = Vec::new();
+    loop {
+        if let Ok(byte) = block!(serial.read()) {
+            buffer.push(byte);
+            ipln!("Ok {:?}", buffer);
+            block!(serial.write(byte)).ok();
+        } else {
+            ipln!("Error");
+        }
+    }
 }
 
 // IDLE LOOP
@@ -44,15 +60,6 @@ fn idle() -> ! {
     }
 }
 
-// TASKS
-// Send back the received byte
-fn loopback(_t: &mut Threshold, r: USART2::Resources) {
-    let serial = Serial(&**r.USART2);
-
-    let byte = serial.read().unwrap();
-    serial.write(byte).unwrap();
-}
-
 // 1. compile and run the project at 16MHz
 // make sure its running (not paused)
 // start a terminal program, e.g., `moserial`