Clean up examples

Author: usbalbin

examples/comp.rs

@@ -32,6 +32,8 @@ fn main() -> ! {
     let pa0 = gpioa.pa0.into_analog();
     let comp1 = comp1.comparator(pa1, pa0, Config::default(), &rcc.clocks);
     let comp1 = comp1.enable();
+
+    // led1 pa1 will be updated manually when to match comp1 value
     let mut led1 = gpioa.pa5.into_push_pull_output();
 
     let pa7 = gpioa.pa7.into_analog();
@@ -50,6 +52,7 @@ fn main() -> ! {
     let _comp2 = comp2.enable().lock();
 
     loop {
+        // Read comp1 output and update led1 accordingly
         match comp1.output() {
             true => led1.set_high().unwrap(),
             false => led1.set_low().unwrap(),

examples/comp_w_dac.rs

@@ -25,12 +25,16 @@ fn main() -> ! {
     let mut delay = cp.SYST.delay(&rcc.clocks);
 
     let gpioa = dp.GPIOA.split(&mut rcc);
-    let dac1ch1 = dp.DAC1.constrain((gpioa.pa4, Dac1IntSig1), &mut rcc);
 
+    // Set up DAC to output to pa4 and to internal signal Dac1IntSig1
+    // which just so happens is compatible with comp1
+    let dac1ch1 = dp.DAC1.constrain((gpioa.pa4, Dac1IntSig1), &mut rcc);
     let mut dac = dac1ch1.calibrate_buffer(&mut delay).enable();
 
     let (comp1, _comp2, ..) = dp.COMP.split(&mut rcc);
     let pa1 = gpioa.pa1.into_analog();
+
+    // Set up comparator with pa1 as positive, and the DAC as negative input
     let comp = comp1.comparator(
         pa1,
         &dac,
@@ -47,6 +51,12 @@ fn main() -> ! {
     let mut dir = Direction::Upcounting;
     let mut val = 0;
 
+    // Manually step the DAC's value to produce a triangle wave
+    //
+    // This will produce a pwm-like signal at pa0 with the duty controlled by pa1
+    // where
+    // * 0V   at p1 =>   0% duty
+    // * VDDA at p1 => 100% duty
     loop {
         dac.set_value(val);
         match val {

examples/dac.rs

@@ -31,21 +31,28 @@ fn main() -> ! {
     let gpioa = dp.GPIOA.split(&mut rcc);
     let (dac1ch1, dac1ch2) = dp.DAC1.constrain((gpioa.pa4, gpioa.pa5), &mut rcc);
 
+    // dac_manual will have its value set manually
     let mut dac_manual = dac1ch1.calibrate_buffer(&mut delay).enable();
+
+    // dac_generator will have its value set automatically from its internal noise generator
     let mut dac_generator = dac1ch2.enable_generator(GeneratorConfig::noise(11));
 
     let mut dir = Direction::Upcounting;
     let mut val = 0;
 
     loop {
+        // This will pull out a new value from the noise generator and apply it to the DAC
         dac_generator.trigger();
+
+        // This will manually set the DAC's value
         dac_manual.set_value(val);
         match val {
             0 => dir = Direction::Upcounting,
             4095 => dir = Direction::Downcounting,
             _ => (),
         };
 
+        // Step manually set value as a triangle wave
         match dir {
             Direction::Upcounting => val += 1,
             Direction::Downcounting => val -= 1,