diff --git a/dma_gpio2/src/bin/main.rs b/dma_gpio2/src/bin/main.rs index e2b9f85..f13b92e 100644 --- a/dma_gpio2/src/bin/main.rs +++ b/dma_gpio2/src/bin/main.rs @@ -4,10 +4,8 @@ use defmt::*; use embassy_executor::Spawner; -use embassy_futures::yield_now; use embassy_stm32::dma::Request; use embassy_stm32::gpio::{Input, Output, Level, Pull, Speed}; -use embassy_sync::{blocking_mutex::raw::CriticalSectionRawMutex, pipe::Pipe}; use embassy_time::{Duration, Timer}; use embassy_stm32::dma::{TransferOptions, WritableRingBuffer}; use dma_gpio::software_uart::{ @@ -15,86 +13,83 @@ use dma_gpio::software_uart::{ gpio_dma_uart_tx::encode_uart_frames, debug::dump_tim6_regs, }; -use dma_gpio::config::{BAUD, TX_PIN_BIT, RX_OVERSAMPLE, TX_OVERSAMPLE}; -use dma_gpio::config::{TX_RING_BYTES, RX_RING_BYTES, PIPE_RX_SIZE}; -use dma_gpio::software_uart::dump_dma_ch0_regs; +use dma_gpio::config::{BAUD, TX_PIN_BIT, TX_OVERSAMPLE, TX_RING_BYTES}; use static_cell::StaticCell; +use core::slice; use {defmt_rtt as _, panic_probe as _}; -// kapitola 17.4.11 - 2 casovace pre 2 DMA -// pub const TIM6_UP_REQ: Request = 4; // Table 137: tim6_upd_dma, strana 687 STM32U5xx datasheet -pub const TIM6_UP_REQ: u8 = 4; - +pub const TIM6_UP_REQ: Request = 4; static TX_RING: StaticCell<[u32; TX_RING_BYTES]> = StaticCell::new(); #[embassy_executor::main] -async fn main(spawner: Spawner) { +async fn main(_spawner: Spawner) { let p = embassy_stm32::init(Default::default()); - info!("Hehe"); - + info!("DMA UART TX - Direct Buffer Modification"); + let _rx = Input::new(p.PA3, Pull::Up); let _tx = Output::new(p.PA2, Level::High, Speed::VeryHigh); - + init_tim6_for_uart(p.TIM6, BAUD, TX_OVERSAMPLE); dump_tim6_regs(); - - // Safe one-time init from StaticCell - let tx_ring_mem: &mut [u32; TX_RING_BYTES] = TX_RING.init([0; TX_RING_BYTES]); - + + // Initialize buffer - keep reference for modification + let tx_ring_mem: &'static mut [u32; TX_RING_BYTES] = TX_RING.init([0; TX_RING_BYTES]); + + // Fill with UART idle state (pin high) let pin_mask = 1u32 << TX_PIN_BIT; - for (i, w) in tx_ring_mem.iter_mut().enumerate() { - *w = if (i & 1) == 0 { 0 } else { pin_mask }; + for word in tx_ring_mem.iter_mut() { + *word = pin_mask; } - - // Create and start the TX DMA ring in main. - // let bsrr_ptr = embassy_stm32::pac::GPIOA.bsrr().as_ptr() as *mut u32; + + // Create DMA ring buffer with a SEPARATE slice created from raw parts + // This allows us to keep modifying tx_ring_mem let odr_ptr = embassy_stm32::pac::GPIOA.odr().as_ptr() as *mut u32; - let mut tx_opts = TransferOptions::default(); - tx_opts.half_transfer_ir = true; - tx_opts.complete_transfer_ir = true; - - // SAFETY: tx_ring_mem is exclusive + let tx_opts = TransferOptions::default(); + let mut tx_ring = unsafe { + // Create a separate mutable slice pointing to the same memory + let dma_slice = slice::from_raw_parts_mut( + tx_ring_mem.as_mut_ptr(), + tx_ring_mem.len() + ); + WritableRingBuffer::new( p.GPDMA1_CH0, TIM6_UP_REQ, odr_ptr, - tx_ring_mem, + dma_slice, tx_opts, ) }; - // Start DMA + tx_ring.start(); - info!("TX DMA ring started"); - dump_dma_ch0_regs(); - + info!("DMA started - continuously reading from buffer"); + + // Temporary buffer for encoding let mut frame_buf = [0u32; 4096]; - + loop { - info!("tick start"); Timer::after(Duration::from_millis(400)).await; - info!("tick end"); - - // PHASE 1A (safest to validate hardware first): do nothing here; the DMA already - // streams the primed toggle pattern in tx_ring_mem. You should see PA2 toggling. - // Uncomment PHASE 1B below once you confirm toggling on a scope/LED. - - // PHASE 1B: actively queue new data (only after confirming DMA advances). - let used = 256.min(frame_buf.len()); - for i in 0..used { frame_buf[i] = if (i & 1) == 0 { 0 } else { pin_mask }; } - info!("a"); - let free = tx_ring.capacity() - tx_ring.len().unwrap_or(0); - if free >= used { - if let Err(e) = tx_ring.write_exact(&frame_buf[..used]).await { - warn!("DMA ring write error: {:?}", e); - } else { - info!("Frame queued to DMA ring (free={})", free); - } - } else { - warn!("Skipping write (free={}, need={})", free, used); + + // Encode the UART frames + let frame_len = encode_uart_frames( + TX_PIN_BIT, + b"Hello marshmallow\r\n", + &mut frame_buf + ).await; + + info!("Encoded {} words, copying to buffer...", frame_len); + + // Copy directly into the ring buffer memory + // DMA will automatically read and transmit this! + let copy_len = frame_len.min(TX_RING_BYTES); + tx_ring_mem[..copy_len].copy_from_slice(&frame_buf[..copy_len]); + + // Fill rest with idle state + for i in copy_len..TX_RING_BYTES { + tx_ring_mem[i] = pin_mask; } - info!("b"); - - yield_now().await; + + info!("Buffer updated - DMA transmitting now"); } }