serial dma TX

src/main.rs

@@ -9,12 +9,13 @@
 #![no_std]
 #![no_main]
 
+use cortex_m::singleton;
 use panic_halt as _;
 
 use nb::block;
 
 use cortex_m_rt::entry;
-use stm32f1xx_hal::{pac, prelude::*, rcc::Config, timer::Timer};
+use stm32f1xx_hal::{pac, prelude::*, rcc, serial, timer::Timer};
 
 #[entry]
 fn main() -> ! {
@@ -31,7 +32,7 @@ fn main() -> ! {
     // Freeze the configuration of all the clocks in the system and store the frozen frequencies in
     // `clocks`
     let clocks = rcc.cfgr.freeze_with_config(
-        Config {
+        rcc::Config {
             // HSE frequency
             hse: Some(8_000_000),
             // PLLMUL represented by an integer -2
@@ -46,8 +47,36 @@ fn main() -> ! {
     );
 
     // Acquire the GPIOC peripheral
+    let mut gpioa = dp.GPIOA.split();
     let mut gpioc = dp.GPIOC.split();
 
+    let mut afio = dp.AFIO.constrain();
+    let dma1 = dp.DMA1.split();
+
+    // USART1
+    let tx = gpioa.pa9.into_alternate_push_pull(&mut gpioa.crh);
+    let rx = gpioa.pa10; //.into_pull_up_input(&mut gpioa.crh);
+
+    let serial = serial::Serial::new(
+        dp.USART1,
+        (tx, rx),
+        &mut afio.mapr,
+        serial::Config {
+            baudrate: 9_600.bps(),
+            ..Default::default()
+        },
+        &clocks,
+    );
+
+    let tx = serial.tx.with_dma(dma1.4);
+    let buf = singleton!(: [u8; 255] = [0b01010101; 255]).unwrap();
+
+    let xfer = tx.write(buf);
+    while !xfer.is_done() {}
+
+    // while circ_buffer.readable_half().unwrap() != dma::Half::First {}
+    // let _first_half = circ_buffer.peek(|half, _| *half).unwrap();
+
     // Configure gpio C pin 13 as a push-pull output. The `crh` register is passed to the function
     // in order to configure the port. For pins 0-7, crl should be passed instead.
     let mut led = gpioc.pc13.into_push_pull_output(&mut gpioc.crh);