[embassy-stm32] added comments explaining multiprio interrupts

1 files changed, 4 insertions, 0 deletions

diff --git a/examples/stm32f3/src/bin/multiprio.rs b/examples/stm32f3/src/bin/multiprio.rs
index 328447210..3a3059db1 100644
--- a/examples/stm32f3/src/bin/multiprio.rs
+++ b/examples/stm32f3/src/bin/multiprio.rs
@@ -127,6 +127,10 @@ fn main() -> ! {
 
     let _p = embassy_stm32::init(Default::default());
 
+    // STM32s don’t have software-defined interrupts, so just use any free interrupt vectors which aren’t used
+    // by the rest of your application. In this case we’re using UART4 and UART5, but there’s nothing special
+    // about them. Any otherwise unused interrupt vector would work exactly the same.
+
     // High-priority executor: UART4, priority level 6
     interrupt::UART4.set_priority(Priority::P6);
     let spawner = EXECUTOR_HIGH.start(interrupt::UART4);