sleep mode commented

.vscode/launch.json

@@ -57,6 +57,81 @@
             },
             "cwd": "${workspaceRoot}",
         },
+        {
+            "type": "cortex-debug",
+            "request": "launch",
+            "servertype": "openocd",
+            "name": "stop",
+            "executable": "./target/thumbv7em-none-eabihf/debug/examples/stop",
+            "configFiles": [
+                "interface/stlink.cfg",
+                "target/stm32f4x.cfg"
+            ],
+            "swoConfig": {
+                "enabled": true,
+                "cpuFrequency": 8000000,
+                "swoFrequency": 2000000, // you may try 1000000 if not working
+                "source": "probe",
+                "decoders": [
+                    {
+                        "type": "console",
+                        "label": "Name",
+                        "port": 0
+                    }
+                ]
+            },
+            "cwd": "${workspaceRoot}"
+        },
+        {
+            "type": "cortex-debug",
+            "request": "launch",
+            "servertype": "openocd",
+            "name": "sleep",
+            "executable": "./target/thumbv7em-none-eabihf/debug/examples/sleep",
+            "configFiles": [
+                "interface/stlink.cfg",
+                "target/stm32f4x.cfg"
+            ],
+            "swoConfig": {
+                "enabled": true,
+                "cpuFrequency": 8000000,
+                "swoFrequency": 2000000, // you may try 1000000 if not working
+                "source": "probe",
+                "decoders": [
+                    {
+                        "type": "console",
+                        "label": "Name",
+                        "port": 0
+                    }
+                ]
+            },
+            "cwd": "${workspaceRoot}"
+        },
+        {
+            "type": "cortex-debug",
+            "request": "launch",
+            "servertype": "openocd",
+            "name": "sleep (release)",
+            "executable": "./target/thumbv7em-none-eabihf/release/examples/sleep",
+            "configFiles": [
+                "interface/stlink.cfg",
+                "target/stm32f4x.cfg"
+            ],
+            "swoConfig": {
+                "enabled": true,
+                "cpuFrequency": 8000000,
+                "swoFrequency": 2000000, // you may try 1000000 if not working
+                "source": "probe",
+                "decoders": [
+                    {
+                        "type": "console",
+                        "label": "Name",
+                        "port": 0
+                    }
+                ]
+            },
+            "cwd": "${workspaceRoot}"
+        },
         {
             "type": "cortex-debug",
             "request": "launch",

examples/sleep.rs

@@ -50,26 +50,6 @@ fn dbg_disable() {
     });
 }
 
-fn wait_cycles(p: &Peripherals, nr_cycles: u32) {
-    let t = p.DWT.cyccnt.read().wrapping_add(nr_cycles);
-    while (p.DWT.cyccnt.read().wrapping_sub(t) as i32) < 0 {}
-}
-
-fn blink(r: &stm32f40x::Peripherals, p: &Peripherals) {
-    r.RCC.ahb1enr.modify(|_, w| w.gpioaen().set_bit());
-    r.GPIOA.moder.modify(|_, w| w.moder5().output_mode());
-    for _ in 0..10 {
-        r.GPIOA.bsrr.write(|w| w.br5().set_bit());
-        for _ in 0..1000 {}
-        // wait_cycles(p, 1000_000);
-
-        r.GPIOA.bsrr.write(|w| w.bs5().set_bit());
-        for _ in 0..1000 {}
-        // wait_cycles(p, 1000_000);
-    }
-    r.GPIOA.moder.modify(|_, w| w.moder5().input_mode());
-}
-
 // the program entry point is ...
 entry!(main);
 // ... this never ending function
@@ -90,45 +70,63 @@ fn main() -> ! {
     r.EXTI.ftsr.modify(|_, w| w.tr1().set_bit());
 
     asm::bkpt();
-    blink(&r, &p);
+    blink();
 
     // p.NVIC.set_pending(Interrupt::EXTI1);
 
     loop {
+        asm::nop(); // put gdb breakpoint here, the MCU and gdb will detect breakpoint
         dbg_disable();
         asm::wfi();
         dbg_enable();
-        asm::bkpt();
+        asm::nop(); // put gdb breakpoint here, in debug mode its caught twice
+                    // first occation (on wakeup), gdb does NOT report span correctly,
+                    // second occation, gdb DEOS report span correctly
+        asm::bkpt(); // here the MCU halt, and gdb detects the asm breakpoint
+                     // gdb continue, will catch the gdb breakpoint at "dbg_disable"
+                     // this is good as it shows that disabling and re-enabling gdb debugging works
+                     // even if the gdb communictation has been disrputed and re-estabished, nice!
     }
-    // asm::bkpt();
-    loop {}
 }
+// the dbg_sleep, and dbg_stop both set deos not prohibit sleep mode debugging (error?)
+// the bdg_standby set further reduces power, and prohibits debugging
+// the behavior seems not to comply with the documentation
+
+// as expected debugging release code puts the gdb breakpoint at the wrong position
+// as expected the initial breakpoint after wakeup deos not register in gdb correctly
+// also the blink loop becomes to fast to observe
 
 // bind the EXTI1 handler
 interrupt!(EXTI1, exti1);
 
 // unsafe version where we access GPIOA through the (raw) pointer
-fn blink2() {
+fn blink() {
+    #[allow(non_snake_case)]
     let GPIOA = unsafe { &*stm32f40x::GPIOA::ptr() };
+    #[allow(non_snake_case)]
+    let RCC = unsafe { &*stm32f40x::RCC::ptr() };
+    RCC.ahb1enr.modify(|_, w| w.gpioaen().set_bit());
     GPIOA.moder.modify(|_, w| w.moder5().output_mode());
     for _ in 0..10 {
         GPIOA.bsrr.write(|w| w.br5().set_bit());
-        for _ in 0..1000 {}
+        for _ in 0..1000 {
+            asm::nop();
+        }
         // wait_cycles(p, 1000_000);
 
         GPIOA.bsrr.write(|w| w.bs5().set_bit());
-        for _ in 0..1000 {}
+        for _ in 0..1000 {
+            asm::nop();
+        }
         // wait_cycles(p, 1000_000);
     }
     GPIOA.moder.modify(|_, w| w.moder5().input_mode());
+    RCC.ahb1enr.modify(|_, w| w.gpioaen().clear_bit());
 }
 
-use cortex_m::interrupt::Nr;
 // the exti1 interrupt implementation
 fn exti1() {
-    // dbg_enable();
-    // asm::bkpt();
-    blink2(); // it will take some time so bounces are likely gone
+    blink(); // it will take some time so bounces are likely gone
 
     // // let's try to "fake" access to GPIOA
     // // let g = stm32f40x::GPIOA {