cpu polling instead of dma

semestralka_1e_tx_bez_dma/src/bin/main.rs

@@ -102,7 +102,8 @@ async fn main(spawner: Spawner) {
     
     let bsrr_ptr = embassy_stm32::pac::GPIOB.bsrr().as_ptr() as *mut u32; // POZOR B REGISTER
     // let odr_ptr = embassy_stm32::pac::GPIOA.odr().as_ptr() as *mut u32; // NEEDS DECODE CHANGE
-    spawner.spawn(tx_dma_task(p.GPDMA1_CH0, bsrr_ptr, sw_tx_ring, &PIPE_SW_TX).unwrap());
+    // spawner.spawn(tx_dma_task(p.GPDMA1_CH0, bsrr_ptr, sw_tx_ring, &PIPE_SW_TX).unwrap());
+    spawner.spawn(tx_cpu_task(bsrr_ptr, p.TIM6, &PIPE_SW_TX)).unwrap();
     // EDN OF SOFTWARE UART 
 
 
@@ -115,6 +116,13 @@ async fn main(spawner: Spawner) {
         // Timer::after(Duration::from_millis(100)).await;
         // info!("tick end");
 
+        let n = PIPE_SW_TX.read(&mut buf).await;
+        if n > 0 {
+            for &byte in &buf[..n] {
+                send_byte_cpu(&tx_pin, p.TIM6, byte).await;
+            }
+        }        
+
         counter += 1;
         let msg = if counter % 2 == 0 {
             b"AAAAA\n"
@@ -164,3 +172,42 @@ pub async fn bridge_usart2_rx_to_usart1_tx(
         }
     }
 }
+
+#[embassy_executor::task]
+pub async fn tx_cpu_task(
+    bsrr_ptr: *mut u32,
+    tim6: embassy_stm32::peripherals::TIM6,
+    pipe_tx: &'static embassy_sync::pipe::Pipe<embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex,1024,>,
+) {
+    use dma_gpio::config::TX_PIN_BIT;
+    use dma_gpio::software_uart::uart_emulation::{encode_uart_byte_cfg, UART_CFG};
+
+    let tim6_regs = unsafe { &*embassy_stm32::pac::TIM6::ptr() };
+    let mut rx_buf = [0u8; 256];
+    let mut frame_buf = [0u32; 32];
+    let mut wait_tick = || async {
+        loop {
+            if tim6_regs.sr().read() & 1 != 0 { 
+                tim6_regs.sr().write(|w| w & !1);
+                break;
+            }
+            embassy_futures::yield_now().await;
+        }
+    };
+
+    loop {
+        let n = pipe_tx.read(&mut rx_buf).await;
+        if n == 0 {
+            embassy_futures::yield_now().await;
+            continue;
+        }
+
+        for &byte in &rx_buf[..n] {
+            let used = encode_uart_byte_cfg(TX_PIN_BIT, byte, &UART_CFG, &mut frame_buf);
+            for word in &frame_buf[..used] {
+                unsafe { core::ptr::write_volatile(bsrr_ptr, *word) };
+                wait_tick().await;
+            }
+        }
+    }
+}