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Diffstat (limited to 'examples/mcxa/src/bin/dma_ping_pong_transfer.rs')
| -rw-r--r-- | examples/mcxa/src/bin/dma_ping_pong_transfer.rs | 376 |
1 files changed, 376 insertions, 0 deletions
diff --git a/examples/mcxa/src/bin/dma_ping_pong_transfer.rs b/examples/mcxa/src/bin/dma_ping_pong_transfer.rs new file mode 100644 index 000000000..f8f543382 --- /dev/null +++ b/examples/mcxa/src/bin/dma_ping_pong_transfer.rs | |||
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| 1 | //! DMA ping-pong/double-buffer transfer example for MCXA276. | ||
| 2 | //! | ||
| 3 | //! This example demonstrates two approaches for ping-pong/double-buffering: | ||
| 4 | //! | ||
| 5 | //! ## Approach 1: Scatter/Gather with linked TCDs (manual) | ||
| 6 | //! - Two TCDs link to each other for alternating transfers | ||
| 7 | //! - Uses custom handler that delegates to on_interrupt() then signals completion | ||
| 8 | //! - Note: With ESG=1, DONE bit is cleared by hardware when next TCD loads, | ||
| 9 | //! so we need an AtomicBool to track completion | ||
| 10 | //! | ||
| 11 | //! ## Approach 2: Half-transfer interrupt with wait_half() (NEW!) | ||
| 12 | //! - Single continuous transfer over entire buffer | ||
| 13 | //! - Uses half-transfer interrupt to know when first half is ready | ||
| 14 | //! - Application can process first half while second half is being filled | ||
| 15 | //! | ||
| 16 | //! # Embassy-style features demonstrated: | ||
| 17 | //! - `DmaChannel::new()` for channel creation | ||
| 18 | //! - Scatter/gather with linked TCDs | ||
| 19 | //! - Custom handler that delegates to HAL's `on_interrupt()` (best practice) | ||
| 20 | //! - Standard `DmaCh1InterruptHandler` with `bind_interrupts!` macro | ||
| 21 | //! - NEW: `wait_half()` for half-transfer interrupt handling | ||
| 22 | |||
| 23 | #![no_std] | ||
| 24 | #![no_main] | ||
| 25 | |||
| 26 | use core::sync::atomic::{AtomicBool, Ordering}; | ||
| 27 | |||
| 28 | use embassy_executor::Spawner; | ||
| 29 | use embassy_mcxa::clocks::config::Div8; | ||
| 30 | use embassy_mcxa::dma::{self, DmaCh1InterruptHandler, DmaChannel, Tcd, TransferOptions}; | ||
| 31 | use embassy_mcxa::lpuart::{Blocking, Config, Lpuart, LpuartTx}; | ||
| 32 | use embassy_mcxa::{bind_interrupts, pac}; | ||
| 33 | use {defmt_rtt as _, embassy_mcxa as hal, panic_probe as _}; | ||
| 34 | |||
| 35 | // Source and destination buffers for Approach 1 (scatter/gather) | ||
| 36 | static mut SRC: [u32; 8] = [1, 2, 3, 4, 5, 6, 7, 8]; | ||
| 37 | static mut DST: [u32; 8] = [0; 8]; | ||
| 38 | |||
| 39 | // Source and destination buffers for Approach 2 (wait_half) | ||
| 40 | static mut SRC2: [u32; 8] = [0xA1, 0xA2, 0xA3, 0xA4, 0xB1, 0xB2, 0xB3, 0xB4]; | ||
| 41 | static mut DST2: [u32; 8] = [0; 8]; | ||
| 42 | |||
| 43 | // TCD pool for scatter/gather - must be 32-byte aligned | ||
| 44 | #[repr(C, align(32))] | ||
| 45 | struct TcdPool([Tcd; 2]); | ||
| 46 | |||
| 47 | static mut TCD_POOL: TcdPool = TcdPool( | ||
| 48 | [Tcd { | ||
| 49 | saddr: 0, | ||
| 50 | soff: 0, | ||
| 51 | attr: 0, | ||
| 52 | nbytes: 0, | ||
| 53 | slast: 0, | ||
| 54 | daddr: 0, | ||
| 55 | doff: 0, | ||
| 56 | citer: 0, | ||
| 57 | dlast_sga: 0, | ||
| 58 | csr: 0, | ||
| 59 | biter: 0, | ||
| 60 | }; 2], | ||
| 61 | ); | ||
| 62 | |||
| 63 | // AtomicBool to track scatter/gather completion | ||
| 64 | // Note: With ESG=1, DONE bit is cleared by hardware when next TCD loads, | ||
| 65 | // so we need this flag to detect when each transfer completes | ||
| 66 | static TRANSFER_DONE: AtomicBool = AtomicBool::new(false); | ||
| 67 | |||
| 68 | // Custom handler for scatter/gather that delegates to HAL's on_interrupt() | ||
| 69 | // This follows the "interrupts as threads" pattern - the handler does minimal work | ||
| 70 | // (delegates to HAL + sets a flag) and the main task does the actual processing | ||
| 71 | pub struct PingPongDmaHandler; | ||
| 72 | |||
| 73 | impl embassy_mcxa::interrupt::typelevel::Handler<embassy_mcxa::interrupt::typelevel::DMA_CH0> for PingPongDmaHandler { | ||
| 74 | unsafe fn on_interrupt() { | ||
| 75 | // Delegate to HAL's on_interrupt() which clears INT flag and wakes wakers | ||
| 76 | dma::on_interrupt(0); | ||
| 77 | // Signal completion for polling (needed because ESG clears DONE bit) | ||
| 78 | TRANSFER_DONE.store(true, Ordering::Release); | ||
| 79 | } | ||
| 80 | } | ||
| 81 | |||
| 82 | // Bind DMA channel interrupts | ||
| 83 | // CH0: Custom handler for scatter/gather (delegates to on_interrupt + sets flag) | ||
| 84 | // CH1: Standard handler for wait_half() demo | ||
| 85 | bind_interrupts!(struct Irqs { | ||
| 86 | DMA_CH0 => PingPongDmaHandler; | ||
| 87 | DMA_CH1 => DmaCh1InterruptHandler; | ||
| 88 | }); | ||
| 89 | |||
| 90 | /// Helper to write a u32 as decimal ASCII to UART | ||
| 91 | fn write_u32(tx: &mut LpuartTx<'_, Blocking>, val: u32) { | ||
| 92 | let mut buf = [0u8; 10]; | ||
| 93 | let mut n = val; | ||
| 94 | let mut i = buf.len(); | ||
| 95 | |||
| 96 | if n == 0 { | ||
| 97 | tx.blocking_write(b"0").ok(); | ||
| 98 | return; | ||
| 99 | } | ||
| 100 | |||
| 101 | while n > 0 { | ||
| 102 | i -= 1; | ||
| 103 | buf[i] = b'0' + (n % 10) as u8; | ||
| 104 | n /= 10; | ||
| 105 | } | ||
| 106 | |||
| 107 | tx.blocking_write(&buf[i..]).ok(); | ||
| 108 | } | ||
| 109 | |||
| 110 | /// Helper to print a buffer to UART | ||
| 111 | fn print_buffer(tx: &mut LpuartTx<'_, Blocking>, buf_ptr: *const u32, len: usize) { | ||
| 112 | tx.blocking_write(b"[").ok(); | ||
| 113 | unsafe { | ||
| 114 | for i in 0..len { | ||
| 115 | write_u32(tx, *buf_ptr.add(i)); | ||
| 116 | if i < len - 1 { | ||
| 117 | tx.blocking_write(b", ").ok(); | ||
| 118 | } | ||
| 119 | } | ||
| 120 | } | ||
| 121 | tx.blocking_write(b"]").ok(); | ||
| 122 | } | ||
| 123 | |||
| 124 | #[embassy_executor::main] | ||
| 125 | async fn main(_spawner: Spawner) { | ||
| 126 | // Small delay to allow probe-rs to attach after reset | ||
| 127 | for _ in 0..100_000 { | ||
| 128 | cortex_m::asm::nop(); | ||
| 129 | } | ||
| 130 | |||
| 131 | let mut cfg = hal::config::Config::default(); | ||
| 132 | cfg.clock_cfg.sirc.fro_12m_enabled = true; | ||
| 133 | cfg.clock_cfg.sirc.fro_lf_div = Some(Div8::no_div()); | ||
| 134 | let p = hal::init(cfg); | ||
| 135 | |||
| 136 | defmt::info!("DMA ping-pong transfer example starting..."); | ||
| 137 | |||
| 138 | // Enable DMA interrupt (DMA clock/reset/init is handled automatically by HAL) | ||
| 139 | unsafe { | ||
| 140 | cortex_m::peripheral::NVIC::unmask(pac::Interrupt::DMA_CH0); | ||
| 141 | } | ||
| 142 | |||
| 143 | let config = Config { | ||
| 144 | baudrate_bps: 115_200, | ||
| 145 | ..Default::default() | ||
| 146 | }; | ||
| 147 | |||
| 148 | let lpuart = Lpuart::new_blocking(p.LPUART2, p.P2_2, p.P2_3, config).unwrap(); | ||
| 149 | let (mut tx, _rx) = lpuart.split(); | ||
| 150 | |||
| 151 | tx.blocking_write(b"EDMA ping-pong transfer example begin.\r\n\r\n") | ||
| 152 | .unwrap(); | ||
| 153 | |||
| 154 | // Initialize buffers | ||
| 155 | unsafe { | ||
| 156 | SRC = [1, 2, 3, 4, 5, 6, 7, 8]; | ||
| 157 | DST = [0; 8]; | ||
| 158 | } | ||
| 159 | |||
| 160 | tx.blocking_write(b"Source Buffer: ").unwrap(); | ||
| 161 | print_buffer(&mut tx, core::ptr::addr_of!(SRC) as *const u32, 8); | ||
| 162 | tx.blocking_write(b"\r\n").unwrap(); | ||
| 163 | |||
| 164 | tx.blocking_write(b"Destination Buffer (before): ").unwrap(); | ||
| 165 | print_buffer(&mut tx, core::ptr::addr_of!(DST) as *const u32, 8); | ||
| 166 | tx.blocking_write(b"\r\n").unwrap(); | ||
| 167 | |||
| 168 | tx.blocking_write(b"Configuring ping-pong DMA with Embassy-style API...\r\n") | ||
| 169 | .unwrap(); | ||
| 170 | |||
| 171 | let dma_ch0 = DmaChannel::new(p.DMA_CH0); | ||
| 172 | |||
| 173 | // Configure ping-pong transfer using direct TCD access: | ||
| 174 | // This sets up TCD0 and TCD1 in RAM, and loads TCD0 into the channel. | ||
| 175 | // TCD0 transfers first half (SRC[0..4] -> DST[0..4]), links to TCD1. | ||
| 176 | // TCD1 transfers second half (SRC[4..8] -> DST[4..8]), links to TCD0. | ||
| 177 | unsafe { | ||
| 178 | let tcds = &mut *core::ptr::addr_of_mut!(TCD_POOL.0); | ||
| 179 | let src_ptr = core::ptr::addr_of!(SRC) as *const u32; | ||
| 180 | let dst_ptr = core::ptr::addr_of_mut!(DST) as *mut u32; | ||
| 181 | |||
| 182 | let half_len = 4usize; | ||
| 183 | let half_bytes = (half_len * 4) as u32; | ||
| 184 | |||
| 185 | let tcd0_addr = &tcds[0] as *const _ as u32; | ||
| 186 | let tcd1_addr = &tcds[1] as *const _ as u32; | ||
| 187 | |||
| 188 | // TCD0: First half -> Links to TCD1 | ||
| 189 | tcds[0] = Tcd { | ||
| 190 | saddr: src_ptr as u32, | ||
| 191 | soff: 4, | ||
| 192 | attr: 0x0202, // 32-bit src/dst | ||
| 193 | nbytes: half_bytes, | ||
| 194 | slast: 0, | ||
| 195 | daddr: dst_ptr as u32, | ||
| 196 | doff: 4, | ||
| 197 | citer: 1, | ||
| 198 | dlast_sga: tcd1_addr as i32, | ||
| 199 | csr: 0x0012, // ESG | INTMAJOR | ||
| 200 | biter: 1, | ||
| 201 | }; | ||
| 202 | |||
| 203 | // TCD1: Second half -> Links to TCD0 | ||
| 204 | tcds[1] = Tcd { | ||
| 205 | saddr: src_ptr.add(half_len) as u32, | ||
| 206 | soff: 4, | ||
| 207 | attr: 0x0202, | ||
| 208 | nbytes: half_bytes, | ||
| 209 | slast: 0, | ||
| 210 | daddr: dst_ptr.add(half_len) as u32, | ||
| 211 | doff: 4, | ||
| 212 | citer: 1, | ||
| 213 | dlast_sga: tcd0_addr as i32, | ||
| 214 | csr: 0x0012, | ||
| 215 | biter: 1, | ||
| 216 | }; | ||
| 217 | |||
| 218 | // Load TCD0 into hardware registers | ||
| 219 | dma_ch0.load_tcd(&tcds[0]); | ||
| 220 | } | ||
| 221 | |||
| 222 | tx.blocking_write(b"Triggering first half transfer...\r\n").unwrap(); | ||
| 223 | |||
| 224 | // Trigger first transfer (first half: SRC[0..4] -> DST[0..4]) | ||
| 225 | unsafe { | ||
| 226 | dma_ch0.trigger_start(); | ||
| 227 | } | ||
| 228 | |||
| 229 | // Wait for first half | ||
| 230 | while !TRANSFER_DONE.load(Ordering::Acquire) { | ||
| 231 | cortex_m::asm::nop(); | ||
| 232 | } | ||
| 233 | TRANSFER_DONE.store(false, Ordering::Release); | ||
| 234 | |||
| 235 | tx.blocking_write(b"First half transferred.\r\n").unwrap(); | ||
| 236 | tx.blocking_write(b"Triggering second half transfer...\r\n").unwrap(); | ||
| 237 | |||
| 238 | // Trigger second transfer (second half: SRC[4..8] -> DST[4..8]) | ||
| 239 | unsafe { | ||
| 240 | dma_ch0.trigger_start(); | ||
| 241 | } | ||
| 242 | |||
| 243 | // Wait for second half | ||
| 244 | while !TRANSFER_DONE.load(Ordering::Acquire) { | ||
| 245 | cortex_m::asm::nop(); | ||
| 246 | } | ||
| 247 | TRANSFER_DONE.store(false, Ordering::Release); | ||
| 248 | |||
| 249 | tx.blocking_write(b"Second half transferred.\r\n\r\n").unwrap(); | ||
| 250 | |||
| 251 | tx.blocking_write(b"EDMA ping-pong transfer example finish.\r\n\r\n") | ||
| 252 | .unwrap(); | ||
| 253 | tx.blocking_write(b"Destination Buffer (after): ").unwrap(); | ||
| 254 | print_buffer(&mut tx, core::ptr::addr_of!(DST) as *const u32, 8); | ||
| 255 | tx.blocking_write(b"\r\n\r\n").unwrap(); | ||
| 256 | |||
| 257 | // Verify: DST should match SRC | ||
| 258 | let mut mismatch = false; | ||
| 259 | unsafe { | ||
| 260 | let src_ptr = core::ptr::addr_of!(SRC) as *const u32; | ||
| 261 | let dst_ptr = core::ptr::addr_of!(DST) as *const u32; | ||
| 262 | for i in 0..8 { | ||
| 263 | if *src_ptr.add(i) != *dst_ptr.add(i) { | ||
| 264 | mismatch = true; | ||
| 265 | break; | ||
| 266 | } | ||
| 267 | } | ||
| 268 | } | ||
| 269 | |||
| 270 | if mismatch { | ||
| 271 | tx.blocking_write(b"FAIL: Approach 1 mismatch detected!\r\n").unwrap(); | ||
| 272 | defmt::error!("FAIL: Approach 1 mismatch detected!"); | ||
| 273 | } else { | ||
| 274 | tx.blocking_write(b"PASS: Approach 1 data verified.\r\n\r\n").unwrap(); | ||
| 275 | defmt::info!("PASS: Approach 1 data verified."); | ||
| 276 | } | ||
| 277 | |||
| 278 | // ========================================================================= | ||
| 279 | // Approach 2: Half-Transfer Interrupt with wait_half() (NEW!) | ||
| 280 | // ========================================================================= | ||
| 281 | // | ||
| 282 | // This approach uses a single continuous DMA transfer with half-transfer | ||
| 283 | // interrupt enabled. The wait_half() method allows you to be notified | ||
| 284 | // when the first half of the buffer is complete, so you can process it | ||
| 285 | // while the second half is still being filled. | ||
| 286 | // | ||
| 287 | // Benefits: | ||
| 288 | // - Simpler setup (no TCD pool needed) | ||
| 289 | // - True async/await support | ||
| 290 | // - Good for streaming data processing | ||
| 291 | |||
| 292 | tx.blocking_write(b"--- Approach 2: wait_half() demo ---\r\n\r\n") | ||
| 293 | .unwrap(); | ||
| 294 | |||
| 295 | // Enable DMA CH1 interrupt | ||
| 296 | unsafe { | ||
| 297 | cortex_m::peripheral::NVIC::unmask(pac::Interrupt::DMA_CH1); | ||
| 298 | } | ||
| 299 | |||
| 300 | // Initialize approach 2 buffers | ||
| 301 | unsafe { | ||
| 302 | SRC2 = [0xA1, 0xA2, 0xA3, 0xA4, 0xB1, 0xB2, 0xB3, 0xB4]; | ||
| 303 | DST2 = [0; 8]; | ||
| 304 | } | ||
| 305 | |||
| 306 | tx.blocking_write(b"SRC2: ").unwrap(); | ||
| 307 | print_buffer(&mut tx, core::ptr::addr_of!(SRC2) as *const u32, 8); | ||
| 308 | tx.blocking_write(b"\r\n").unwrap(); | ||
| 309 | |||
| 310 | let dma_ch1 = DmaChannel::new(p.DMA_CH1); | ||
| 311 | |||
| 312 | // Configure transfer with half-transfer interrupt enabled | ||
| 313 | let mut options = TransferOptions::default(); | ||
| 314 | options.half_transfer_interrupt = true; // Enable half-transfer interrupt | ||
| 315 | options.complete_transfer_interrupt = true; | ||
| 316 | |||
| 317 | tx.blocking_write(b"Starting transfer with half_transfer_interrupt...\r\n") | ||
| 318 | .unwrap(); | ||
| 319 | |||
| 320 | unsafe { | ||
| 321 | let src = &*core::ptr::addr_of!(SRC2); | ||
| 322 | let dst = &mut *core::ptr::addr_of_mut!(DST2); | ||
| 323 | |||
| 324 | // Create the transfer | ||
| 325 | let mut transfer = dma_ch1.mem_to_mem(src, dst, options); | ||
| 326 | |||
| 327 | // Wait for half-transfer (first 4 elements) | ||
| 328 | tx.blocking_write(b"Waiting for first half...\r\n").unwrap(); | ||
| 329 | let half_ok = transfer.wait_half().await; | ||
| 330 | |||
| 331 | if half_ok { | ||
| 332 | tx.blocking_write(b"Half-transfer complete! First half of DST2: ") | ||
| 333 | .unwrap(); | ||
| 334 | print_buffer(&mut tx, core::ptr::addr_of!(DST2) as *const u32, 4); | ||
| 335 | tx.blocking_write(b"\r\n").unwrap(); | ||
| 336 | tx.blocking_write(b"(Processing first half while second half transfers...)\r\n") | ||
| 337 | .unwrap(); | ||
| 338 | } | ||
| 339 | |||
| 340 | // Wait for complete transfer | ||
| 341 | tx.blocking_write(b"Waiting for second half...\r\n").unwrap(); | ||
| 342 | transfer.await; | ||
| 343 | } | ||
| 344 | |||
| 345 | tx.blocking_write(b"Transfer complete! Full DST2: ").unwrap(); | ||
| 346 | print_buffer(&mut tx, core::ptr::addr_of!(DST2) as *const u32, 8); | ||
| 347 | tx.blocking_write(b"\r\n\r\n").unwrap(); | ||
| 348 | |||
| 349 | // Verify approach 2 | ||
| 350 | let mut mismatch2 = false; | ||
| 351 | unsafe { | ||
| 352 | let src_ptr = core::ptr::addr_of!(SRC2) as *const u32; | ||
| 353 | let dst_ptr = core::ptr::addr_of!(DST2) as *const u32; | ||
| 354 | for i in 0..8 { | ||
| 355 | if *src_ptr.add(i) != *dst_ptr.add(i) { | ||
| 356 | mismatch2 = true; | ||
| 357 | break; | ||
| 358 | } | ||
| 359 | } | ||
| 360 | } | ||
| 361 | |||
| 362 | if mismatch2 { | ||
| 363 | tx.blocking_write(b"FAIL: Approach 2 mismatch!\r\n").unwrap(); | ||
| 364 | defmt::error!("FAIL: Approach 2 mismatch!"); | ||
| 365 | } else { | ||
| 366 | tx.blocking_write(b"PASS: Approach 2 verified.\r\n").unwrap(); | ||
| 367 | defmt::info!("PASS: Approach 2 verified."); | ||
| 368 | } | ||
| 369 | |||
| 370 | tx.blocking_write(b"\r\n=== All ping-pong demos complete ===\r\n") | ||
| 371 | .unwrap(); | ||
| 372 | |||
| 373 | loop { | ||
| 374 | cortex_m::asm::wfe(); | ||
| 375 | } | ||
| 376 | } | ||
