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Merge pull request 'bugfix for updated DMA example' (#20) from dma-bugfix into main
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Reviewed-on: #20
This commit is contained in:
Robin Müller 2024-07-04 15:52:13 +02:00
commit 8d84c61327
1 changed files with 6 additions and 5 deletions
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11
examples/simple/examples/dma.rs
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@ -25,7 +25,8 @@ static DMA_ACTIVE_FLAG: Mutex<Cell<bool>> = Mutex::new(Cell::new(false));
#[link_section = ".sram1"]
static mut DMA_CTRL_BLOCK: DmaCtrlBlock = DmaCtrlBlock::new();
// We can use statically allocated buffers for DMA transfers as well.
// We can use statically allocated buffers for DMA transfers as well, and we can also place
// those into SRAM1.
#[link_section = ".sram1"]
static mut DMA_SRC_BUF: [u16; 36] = [0; 36];
#[link_section = ".sram1"]
@ -135,10 +136,11 @@ fn transfer_example_8_bit(
}
fn transfer_example_16_bit(dma0: &mut DmaChannel, delay_ms: &mut CountdownTimer<pac::Tim0>) {
let dest_buf_ref = unsafe { &mut *core::ptr::addr_of_mut!(DMA_DEST_BUF[0..33]) };
unsafe {
// Set values scaled from 0 to 65535 to verify this is really a 16-bit transfer.
(0..32).for_each(|i| {
DMA_SRC_BUF[i] = (i as u32 * u16::MAX as u32 / (DMA_SRC_BUF.len() - 1) as u32) as u16;
DMA_SRC_BUF[i] = (i as u32 * u16::MAX as u32 / (dest_buf_ref.len() as u32 - 1)) as u16;
});
}
cortex_m::interrupt::free(|cs| {
@ -147,12 +149,11 @@ fn transfer_example_16_bit(dma0: &mut DmaChannel, delay_ms: &mut CountdownTimer<
cortex_m::interrupt::free(|cs| {
DMA_ACTIVE_FLAG.borrow(cs).set(false);
});
let dest_buf_ref = unsafe { &mut *core::ptr::addr_of_mut!(DMA_DEST_BUF[0..32]) };
// Safety: The source and destination buffer are valid for the duration of the DMA transfer.
unsafe {
dma0.prepare_mem_to_mem_transfer_16_bit(
&*core::ptr::addr_of!(DMA_SRC_BUF[0..32]),
dest_buf_ref,
&mut dest_buf_ref[0..32],
)
.expect("error preparing transfer");
}
@ -187,7 +188,7 @@ fn transfer_example_16_bit(dma0: &mut DmaChannel, delay_ms: &mut CountdownTimer<
(0..32).for_each(|i| {
assert_eq!(
dest_buf_ref[i],
(i as u32 * u16::MAX as u32 / (dest_buf_ref.len() - 1) as u32) as u16
(i as u32 * u16::MAX as u32 / (dest_buf_ref.len() as u32 - 1)) as u16
);
});
// Sentinel value, should be 0.