dma tx kind of works

.gdbinit

-target remote :3333
+# target remote :3333
 # monitor reset init
-monitor arm semihosting enable
+# monitor arm semihosting enable
 
 # send captured ITM to the file /tmp/itm.log
 # (the microcontroller SWO pin must be connected to the programmer SWO pin)
@@ -13,4 +13,4 @@ monitor itm port 0 on
 #load
 #step
 # monitor reset halt
-detach
+# detach

.vscode/launch.json

@@ -82,5 +82,29 @@
             ],
             "cwd": "${workspaceRoot}"
         },
+        {
+            "type": "cortex-debug",
+            "request": "launch",
+            "servertype": "openocd",
+            "name": "Debug Microcontroller",
+            "executable": "./target/thumbv7em-none-eabihf/debug/examples/serial-dma-tx",
+            "configFiles": [
+                "interface/stlink.cfg",
+                "target/stm32f4x.cfg"
+            ],
+            "swoConfig": [
+                "enabled": "true",
+                "swoFrequency": "0",
+                "cpuFrequency": "0",
+                "ports": [
+                    [
+                        "number": "0",
+                        "label": "0",
+                        "format": "console",
+                    ]
+                ]
+            ],
+            "cwd": "${workspaceRoot}"
+        }
     ]
 }
\ No newline at end of file

src/dma.rs

@@ -309,7 +309,7 @@ pub mod dma1 {
             }
             asm::bkpt();
             dma.hifcr.write(|w| w.ctcif6().set_bit());
-            dma.s2cr.modify(|_, w| w.en().clear_bit());
+            dma.s6cr.modify(|_, w| w.en().clear_bit());
 
             // TODO can we weaken this compiler barrier?
             // NOTE(compiler_fence) operations on `buffer` should not be reordered

src/serial.rs

@@ -137,6 +137,20 @@ macro_rules! hal {
                         .cr1
                         .write(|w| w.ue().set_bit().re().set_bit().te().set_bit());
 
+                    // disable hardware flow control
+                    // enable DMA TX and RX transfers
+
+                    usart.cr3.write(|w| {
+                        w.rtse()
+                            .clear_bit()
+                            .ctse()
+                            .clear_bit()
+                            .dmat()
+                            .set_bit()
+                            .dmar()
+                            .set_bit()
+                    });
+
                     Serial { usart, pins }
                 }