Possible solution

Labware/Lab8_SwitchLEDinterface/SwitchLEDInterface.c

@@ -3,7 +3,7 @@
 // Runs on LM4F120/TM4C123
 // Use simple programming structures in C to toggle an LED
 // while a button is pressed and turn the LED on when the
-// button is released.  This lab requires external hardware
+// button is released. This lab requires external hardware
 // to be wired to the LaunchPad using the prototyping board.
 // January 15, 2016
 //      Jon Valvano and Ramesh Yerraballi
@@ -12,11 +12,26 @@
 #include "TExaS.h"
 #include "tm4c123gh6pm.h"
 
+#define GPIO_PORTE_DATA_R       (*((volatile unsigned long *)0x400243FC))
+#define GPIO_PORTE_DIR_R        (*((volatile unsigned long *)0x40024400))
+#define GPIO_PORTE_AFSEL_R      (*((volatile unsigned long *)0x40024420))
+#define GPIO_PORTE_PUR_R        (*((volatile unsigned long *)0x40024510))
+#define GPIO_PORTE_DEN_R        (*((volatile unsigned long *)0x4002451C))
+#define GPIO_PORTE_LOCK_R       (*((volatile unsigned long *)0x40024520))
+#define GPIO_PORTE_CR_R         (*((volatile unsigned long *)0x40024524))
+#define GPIO_PORTE_AMSEL_R      (*((volatile unsigned long *)0x40024528))
+#define GPIO_PORTE_PCTL_R       (*((volatile unsigned long *)0x4002452C))
+#define SYSCTL_RCGC2_R          (*((volatile unsigned long *)0x400FE108))
+
 // ***** 2. Global Declarations Section *****
+unsigned long SW4;
+unsigned long Out;
 
 // FUNCTION PROTOTYPES: Each subroutine defined
 void DisableInterrupts(void); // Disable interrupts
 void EnableInterrupts(void);  // Enable interrupts
+void PortE_init(void);        // Init port PE0 PE1
+void Delay1ms(unsigned long msec);
 
 // ***** 3. Subroutines Section *****
 
@@ -25,16 +40,41 @@ void EnableInterrupts(void);  // Enable interrupts
 // To avoid damaging your hardware, ensure that your circuits match the schematic
 // shown in Lab8_artist.sch (PCB Artist schematic file) or 
 // Lab8_artist.pdf (compatible with many various readers like Adobe Acrobat).
-int main(void){ 
+int main(void) { 
 //**********************************************************************
 // The following version tests input on PE0 and output on PE1
 //**********************************************************************
   TExaS_Init(SW_PIN_PE0, LED_PIN_PE1, ScopeOn);  // activate grader and set system clock to 80 MHz
-  
-	
+  PortE_init();
   EnableInterrupts();           // enable interrupts for the grader
   while(1){
-    
+    SW4 = GPIO_PORTE_DATA_R&0x00;
+    if (SW4) {
+      GPIO_PORTE_DATA_R = 0x02;
+    }
+    Delay1ms(100);
   }
-  
 }
+
+void PortE_init() { volatile unsigned long delay;
+  SYSCTL_RCGC2_R |= 0x00000010;      // 1) F clock
+  delay = SYSCTL_RCGC2_R;            // delay to allow clock to stabilize     
+  GPIO_PORTE_AMSEL_R &= 0x00;        // 2) disable analog function
+  GPIO_PORTE_PCTL_R &= 0x00000000;   // 3) GPIO clear bit PCTL  
+  GPIO_PORTE_DIR_R &= ~0x00;         // 4.1) PF0 input,
+  GPIO_PORTE_DIR_R |= 0x01;          // 4.2) PF1 output  
+  GPIO_PORTE_AFSEL_R &= 0x00;        // 5) no alternate function
+  GPIO_PORTE_PUR_R |= 0x10;          // 6) enable pullup resistor on PF4       
+  GPIO_PORTE_DEN_R |= 0x11;          // 7) enable digital pins PF1-PF0
+}
+
+void Delay1ms(unsigned long msec) {
+  unsigned long count;
+  while(msec > 0) {
+    count = 1600;
+    while(count > 0) {
+      count--;
+    }
+    ms--;
+  }
+}
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