moved properly

usart_async_buffered_generalized2/src/uart/driver.rs

@@ -8,7 +8,7 @@ use embassy_sync::pipe::Pipe;
 use embassy_time::Duration;
 use embedded_io_async::{Read, Write};
 
-use crate::safety::{RX_PIPE_CAP, TX_PIPE_CAP};
+use crate::uart::safety::{RX_PIPE_CAP, TX_PIPE_CAP};
 
 pub struct UartHandle {
     pub tx: &'static Pipe<CriticalSectionRawMutex, TX_PIPE_CAP>,

usart_async_buffered_generalized2/src/uart/mod.rs

@@ -1,3 +1,4 @@
 // src/uart/mod.rs
 pub mod driver;
 pub mod usart1;
+pub mod safety;

usart_async_buffered_generalized2/src/uart/safety.rs

@@ -0,0 +1,57 @@
+// src/safety.rs
+use defmt::info;
+use embassy_time::Duration;
+
+// ISR RX ring capacity = RX_BUF len
+const ISR_RX_BUF_CAP: usize = 256;
+// Yield 1/2 the time it takes to fill ISR RX ring.
+const YIELD_MARGIN_NUM: u32 = 1;
+const YIELD_MARGIN_DEN: u32 = 2;
+// Ensure RX_PIPE_CAP can hold this.
+const WORST_MAIN_LATENCY_MS: u32 = 20;
+
+pub const TX_PIPE_CAP: usize = 1024;
+pub const RX_PIPE_CAP: usize = 1024;
+
+
+
+/// Perform safety checks and compute yield timing to avoid buffer overflow.
+///
+/// # Panics
+/// Panics if pipe capacities are too small for the configured baud.
+pub fn preflight_and_suggest_yield_period(baud: u32) -> Duration {
+    // Approx bytes per second for 8N1 (10 bits per byte on the wire)
+    let bytes_per_sec = (baud / 10).max(1);
+
+    // Time until ISR RX ring fills, in microseconds.
+    let t_fill_us = (ISR_RX_BUF_CAP as u64) * 1_000_000u64 / (bytes_per_sec as u64);
+
+    // Choose a yield period as a fraction of t_fill.
+    let yield_us = (t_fill_us as u64)
+        .saturating_mul(YIELD_MARGIN_NUM as u64)
+        / (YIELD_MARGIN_DEN as u64);
+
+    // Verify RX pipe can absorb a worst-case app latency so uart_task
+    // can always forward without dropping when it runs.
+    let required_rx_pipe = (bytes_per_sec as u64) * (WORST_MAIN_LATENCY_MS as u64) / 1000;
+
+    if (RX_PIPE_CAP as u64) < required_rx_pipe {
+        core::panic!(
+            "RX pipe too small: have {}B, need >= {}B for {}ms at {} bps",
+            RX_PIPE_CAP, required_rx_pipe, WORST_MAIN_LATENCY_MS, baud
+        );
+    }
+
+    info!(
+        "Preflight: baud={}, rx_isr={}B, rx_pipe={}B, bytes/s={}, t_fill_us={}, yield_us={}",
+        baud,
+        ISR_RX_BUF_CAP,
+        RX_PIPE_CAP,
+        bytes_per_sec,
+        t_fill_us,
+        yield_us
+    );
+
+    // Never choose zero.
+    Duration::from_micros(yield_us.max(1) as u64)
+}

usart_async_buffered_generalized2/src/uart/usart1.rs

@@ -1,13 +1,11 @@
 // src/uart/usart1.rs
 use defmt::info;
 use embassy_executor::Spawner;
-use embassy_stm32::bind_interrupts;
-use embassy_stm32::usart::BufferedInterruptHandler;
 use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
 use embassy_sync::pipe::Pipe;
 use embassy_time::Duration;
 
-use crate::safety::{preflight_and_suggest_yield_period, RX_PIPE_CAP, TX_PIPE_CAP};
+use crate::uart::safety::{preflight_and_suggest_yield_period, RX_PIPE_CAP, TX_PIPE_CAP};
 use crate::uart::driver::{spawn_for, UartHandle};
 
 // Static pipes and buffers