bare4_1

examples/bare4.rs

@@ -22,9 +22,12 @@ mod address {
     pub const PERIPH_BASE: u32      = 0x40000000;
     pub const AHB1PERIPH_BASE: u32  = PERIPH_BASE + 0x00020000;
     pub const RCC_BASE: u32         = AHB1PERIPH_BASE + 0x3800;
+    // 6.3.11
     pub const RCC_AHB1ENR: u32      = RCC_BASE + 0x30;
     pub const GBPIA_BASE: u32       = AHB1PERIPH_BASE + 0x0000;
+    // 8.4.1
     pub const GPIOA_MODER: u32      = GBPIA_BASE + 0x00;
+    // 8.4.7
     pub const GPIOA_BSRR: u32       = GBPIA_BASE + 0x18;
 }
 
@@ -56,10 +59,12 @@ fn wait(i: u32) {
 #[entry]
 fn main() -> ! {
     // power on GPIOA
+    // 6.3.11
     let r = read_u32(RCC_AHB1ENR); // read
     write_u32(RCC_AHB1ENR, r | 1); // set enable
 
     // configure PA5 as output
+    // 8.4.1
     let r = read_u32(GPIOA_MODER) & !(0b11 << (5 * 2)); // read and mask
     write_u32(GPIOA_MODER, r | 0b01 << (5 * 2)); // set output mode
 
@@ -68,10 +73,12 @@ fn main() -> ! {
 
     loop {
         // set PA5 high
+        // 8.4.7
         write_u32(GPIOA_BSRR, 1 << 5); // set bit, output hight (turn on led)
         wait(10_000);
 
         // set PA5 low
+        // 8.4.7
         write_u32(GPIOA_BSRR, 1 << (5 + 16)); // clear bit, output low (turn off led)
         wait(10_000);
     }
@@ -84,7 +91,7 @@ fn main() -> ! {
 //
 // 1.  Did you enjoy the blinking?
 //
-//    ** your answer here **
+//    ** Yes **
 //
 //    Now lookup the data-sheets, and read each section referred,
 //    6.3.11, 8.4.1, 8.4.7