Merge pull request #2338 from eZioPan/note-on-circular-dma

docs: add a note about circular mode DMA

2 files changed, 8 insertions, 0 deletions

diff --git a/embassy-stm32/src/dma/bdma.rs b/embassy-stm32/src/dma/bdma.rs
index 2f37b1edf..a2b83716d 100644
--- a/embassy-stm32/src/dma/bdma.rs
+++ b/embassy-stm32/src/dma/bdma.rs
@@ -23,6 +23,10 @@ use crate::pac::bdma::{regs, vals};
 #[non_exhaustive]
 pub struct TransferOptions {
     /// Enable circular DMA
+    ///
+    /// Note:
+    /// If you enable circular mode manually, you may want to build and `.await` the `Transfer` in a separate task.
+    /// Since DMA in circular mode need manually stop, `.await` in current task would block the task forever.
     pub circular: bool,
     /// Enable half transfer interrupt
     pub half_transfer_ir: bool,
diff --git a/embassy-stm32/src/dma/dma.rs b/embassy-stm32/src/dma/dma.rs
index 9b47ca5c3..16d02f273 100644
--- a/embassy-stm32/src/dma/dma.rs
+++ b/embassy-stm32/src/dma/dma.rs
@@ -30,6 +30,10 @@ pub struct TransferOptions {
     /// FIFO threshold for DMA FIFO mode. If none, direct mode is used.
     pub fifo_threshold: Option<FifoThreshold>,
     /// Enable circular DMA
+    ///
+    /// Note:
+    /// If you enable circular mode manually, you may want to build and `.await` the `Transfer` in a separate task.
+    /// Since DMA in circular mode need manually stop, `.await` in current task would block the task forever.
     pub circular: bool,
     /// Enable half transfer interrupt
     pub half_transfer_ir: bool,