2.0.8

Author: quantum-leaps

lesson-39/tm4c123-uc_ao-keil/bsp.c

@@ -75,22 +75,28 @@ void App_TCBInitHook    (OS_TCB *ptcb) { (void)ptcb; }
 
 /* BSP functions ===========================================================*/
 void BSP_init(void) {
-    SYSCTL->RCGCGPIO  |= (1U << 5); /* enable Run Mode for GPIOF */
+    /* enable clock for to the peripherals used by this application... */
     SYSCTL->GPIOHBCTL |= (1U << 5); /* enable AHB for GPIOF */
+    SYSCTL->RCGCGPIO  |= (1U << 5); /* enable Run mode for GPIOF */
 
-    /* make sure the Run Mode and AHB-enable take effects
-    * before accessing the peripherals
-    */
-    __ISB(); /* Instruction Synchronization Barrier */
-    __DSB(); /* Data Memory Barrier */
-
+    /* configure LEDs (digital output) */
     GPIOF_AHB->DIR |= (LED_RED | LED_BLUE | LED_GREEN);
     GPIOF_AHB->DEN |= (LED_RED | LED_BLUE | LED_GREEN);
+    GPIOF_AHB->DATA_Bits[LED_RED | LED_BLUE | LED_GREEN] = 0U;
+
+    /* configure switches... */
+
+    /* unlock access to the SW2 pin because it is PROTECTED */
+    GPIOF_AHB->LOCK = 0x4C4F434BU; /* unlock GPIOCR register for SW2 */
+    /* commit the write (cast const away) */
+    *(uint32_t volatile *)&GPIOF_AHB->CR = 0x01U;
+
+    GPIOF_AHB->DIR &= ~(BTN_SW1 | BTN_SW2); /* input */
+    GPIOF_AHB->DEN |= (BTN_SW1 | BTN_SW2); /* digital enable */
+    GPIOF_AHB->PUR |= (BTN_SW1 | BTN_SW2); /* pull-up resistor enable */
 
-    /* configure switch SW1 */
-    GPIOF_AHB->DIR &= ~BTN_SW1; /* input */
-    GPIOF_AHB->DEN |= BTN_SW1; /* digital enable */
-    GPIOF_AHB->PUR |= BTN_SW1; /* pull-up resistor enable */
+    *(uint32_t volatile *)&GPIOF_AHB->CR = 0x00U;
+    GPIOF_AHB->LOCK = 0x0; /* lock GPIOCR register for SW2 */
 }
 /*..........................................................................*/
 void BSP_start(void) {