From fa54dd5849a083b286b2a3f1928428c8704d3d70 Mon Sep 17 00:00:00 2001
From: James Munns <james@onevariable.com>
Date: Fri, 5 Dec 2025 15:22:38 +0100
Subject: Create separate ring buffered RX receiver to encapsulate unsafe

---
 examples/mcxa/Cargo.toml                    |  1 +
 examples/mcxa/src/bin/lpuart_dma.rs         |  2 +-
 examples/mcxa/src/bin/lpuart_ring_buffer.rs | 15 ++++-----------
 3 files changed, 6 insertions(+), 12 deletions(-)

(limited to 'examples')

diff --git a/examples/mcxa/Cargo.toml b/examples/mcxa/Cargo.toml
index 4d0459f41..1ac8eac53 100644
--- a/examples/mcxa/Cargo.toml
+++ b/examples/mcxa/Cargo.toml
@@ -20,6 +20,7 @@ embassy-time-driver = "0.2.1"
 embedded-io-async = "0.6.1"
 heapless = "0.9.2"
 panic-probe = { version = "1.0", features = ["print-defmt"] }
+static_cell = "2.1.1"
 tmp108 = "0.4.0"
 
 [profile.release]
diff --git a/examples/mcxa/src/bin/lpuart_dma.rs b/examples/mcxa/src/bin/lpuart_dma.rs
index 1fc6595e6..34d343452 100644
--- a/examples/mcxa/src/bin/lpuart_dma.rs
+++ b/examples/mcxa/src/bin/lpuart_dma.rs
@@ -14,7 +14,7 @@ use embassy_executor::Spawner;
 use embassy_mcxa::clocks::config::Div8;
 use embassy_mcxa::dma::{DmaCh0InterruptHandler, DmaCh1InterruptHandler};
 use embassy_mcxa::lpuart::{Config, LpuartDma};
-use embassy_mcxa::{bind_interrupts, pac};
+use embassy_mcxa::bind_interrupts;
 use {defmt_rtt as _, embassy_mcxa as hal, panic_probe as _};
 
 // Bind DMA channel interrupts using Embassy-style macro
diff --git a/examples/mcxa/src/bin/lpuart_ring_buffer.rs b/examples/mcxa/src/bin/lpuart_ring_buffer.rs
index 1d1a51970..b707e20f8 100644
--- a/examples/mcxa/src/bin/lpuart_ring_buffer.rs
+++ b/examples/mcxa/src/bin/lpuart_ring_buffer.rs
@@ -23,6 +23,7 @@ use embassy_mcxa::bind_interrupts;
 use embassy_mcxa::clocks::config::Div8;
 use embassy_mcxa::dma::{DmaCh0InterruptHandler, DmaCh1InterruptHandler};
 use embassy_mcxa::lpuart::{Config, LpuartDma, LpuartTxDma};
+use static_cell::ConstStaticCell;
 use {defmt_rtt as _, embassy_mcxa as hal, panic_probe as _};
 
 // Bind DMA channel interrupts
@@ -32,7 +33,7 @@ bind_interrupts!(struct Irqs {
 });
 
 // Ring buffer for RX - power of 2 is ideal for modulo efficiency
-static mut RX_RING_BUFFER: [u8; 64] = [0; 64];
+static RX_RING_BUFFER: ConstStaticCell<[u8; 64]> = ConstStaticCell::new([0; 64]);
 
 /// Helper to write a byte as hex to UART
 fn write_hex<T: embassy_mcxa::lpuart::Instance, C: embassy_mcxa::dma::Channel>(
@@ -75,17 +76,9 @@ async fn main(_spawner: Spawner) {
     tx.blocking_write(b"Setting up circular DMA for UART RX...\r\n")
         .unwrap();
 
+    let buf = RX_RING_BUFFER.take();
     // Set up the ring buffer with circular DMA
-    // The HAL handles: DMA request source, RDMAE enable, circular transfer config, NVIC enable
-    let ring_buf = unsafe {
-        let buf = &mut *core::ptr::addr_of_mut!(RX_RING_BUFFER);
-        rx.setup_ring_buffer(buf)
-    };
-
-    // Enable DMA requests to start continuous reception
-    unsafe {
-        rx.enable_dma_request();
-    }
+    let mut ring_buf = rx.into_ring_dma_rx(buf);
 
     tx.blocking_write(b"Ring buffer ready! Type characters to see them echoed.\r\n")
         .unwrap();
-- 
cgit