PWM Disp

ES/Lab/Lab11/PWM_Keyboard.c

@@ -1,24 +1,21 @@
 #include "LPC17xx.h"
 
-// PWM variables
+volatile unsigned long int duty_cycle = 10;
-volatile unsigned long int duty_cycle = 10;  // Start at 10%
 volatile unsigned long int pwm_counter = 0;
 
-// Pin definitions
+#define LED_SHIFT           4
-#define LED_SHIFT           4   // CNA: P0.4-P0.11
 #define LED_MASK            (0xFF << LED_SHIFT)
 
-// Keypad on CND - ROW-0
+#define COL0                (1<<0)
-#define COL0                (1<<0)   // P2.0
+#define COL1                (1<<1)
-#define COL1                (1<<1)   // P2.1
+#define COL2                (1<<23)
-#define COL2                (1<<23)  // P0.23
+#define COL3                (1<<24)
-#define COL3                (1<<24)  // P0.24
+#define ROW0                (1<<25)
-#define ROW0                (1<<25)  // P0.25
 
 #define COL_MASK_P0         (COL2 | COL3)
 #define COL_MASK_P2         (COL0 | COL1)
 
-#define PWM_PERIOD          100      // 100 steps for percentage
+#define PWM_PERIOD          100
 
 static void delay_ms(unsigned int ms) {
     unsigned int i, j;
@@ -44,22 +41,20 @@ static unsigned int is_row0_pressed(void)
     return !(LPC_GPIO0->FIOPIN & ROW0);
 }
 
-// HIGH-SPEED PWM Interrupt Handler
 void PWM1_IRQHandler(void)
 {
     if (LPC_PWM1->IR & (1 << 0))
     {
-        // Fast software PWM for all 8 LEDs
         if(pwm_counter < duty_cycle)
-            LPC_GPIO0->FIOSET = LED_MASK;  // All LEDs ON
+            LPC_GPIO0->FIOSET = LED_MASK;
         else
-            LPC_GPIO0->FIOCLR = LED_MASK;  // All LEDs OFF
+            LPC_GPIO0->FIOCLR = LED_MASK;
 
         pwm_counter++;
         if(pwm_counter >= PWM_PERIOD)
             pwm_counter = 0;
 
-        LPC_PWM1->IR = (1 << 0);  // Clear interrupt flag
+        LPC_PWM1->IR = (1 << 0);
     }
 }
 
@@ -69,58 +64,46 @@ int main(void)
     unsigned int read_key;
     unsigned int last_key = 0xFF;
 
-    // === PIN CONFIGURATION ===
+    LPC_PINCON->PINSEL0 &= ~(0xFFFF << 8);
-    LPC_PINCON->PINSEL0 &= ~(0xFFFF << 8);   // P0.4-P0.11 as GPIO
+    LPC_PINCON->PINSEL1 &= ~(0xFFFF << 14);
-    LPC_PINCON->PINSEL1 &= ~(0xFFFF << 14);  // P0.23-P0.28 as GPIO
+    LPC_PINCON->PINSEL4 &= ~(0xF << 0);
-    LPC_PINCON->PINSEL4 &= ~(0xF << 0);      // P2.0-P2.1 as GPIO
 
-    // === GPIO SETUP ===
+    LPC_GPIO0->FIODIR |= LED_MASK;
-    LPC_GPIO0->FIODIR |= LED_MASK;       // LEDs output
+    LPC_GPIO0->FIODIR |= COL_MASK_P0;
-    LPC_GPIO0->FIODIR |= COL_MASK_P0;    // Columns output
+    LPC_GPIO2->FIODIR |= COL_MASK_P2;
-    LPC_GPIO2->FIODIR |= COL_MASK_P2;    // Columns output
+    LPC_GPIO0->FIODIR &= ~ROW0;
-    LPC_GPIO0->FIODIR &= ~ROW0;          // Row input
 
-    // Initialize
     LPC_GPIO0->FIOCLR = LED_MASK;
     LPC_GPIO2->FIOSET = COL_MASK_P2;
     LPC_GPIO0->FIOSET = COL_MASK_P0;
 
-    // === HIGH-SPEED PWM CONFIGURATION ===
+    LPC_SC->PCONP |= (1 << 6);
-    LPC_SC->PCONP |= (1 << 6);           // Power on PWM1
 
-    LPC_PWM1->TCR = (1 << 1);            // Reset
+    LPC_PWM1->TCR = (1 << 1);
-    LPC_PWM1->CTCR = 0;                  // Timer mode
+    LPC_PWM1->CTCR = 0;
-    LPC_PWM1->PR = 9;                    // Prescaler = 10
+    LPC_PWM1->PR = 9;
-                                         // 100MHz / 10 = 10MHz timer clock
 
-    LPC_PWM1->MR0 = 100;                 // Match every 100 ticks
+    LPC_PWM1->MR0 = 100;
-                                         // Interrupt rate = 10MHz/100 = 100kHz
+    LPC_PWM1->MCR = (1 << 1) | (1 << 0);
-                                         // PWM frequency = 100kHz/100 = 1kHz
+    LPC_PWM1->LER = (1 << 0);
-                                         // NO VISIBLE FLICKER!
 
-    LPC_PWM1->MCR = (1 << 1) | (1 << 0); // Reset on MR0 + interrupt
+    NVIC_EnableIRQ(PWM1_IRQn);
-    LPC_PWM1->LER = (1 << 0);            // Latch MR0
+    NVIC_SetPriority(PWM1_IRQn, 0);
 
-    NVIC_EnableIRQ(PWM1_IRQn);           // Enable interrupt
+    LPC_PWM1->TCR = (1 << 0) | (1 << 3);
-    NVIC_SetPriority(PWM1_IRQn, 0);      // Highest priority
 
-    LPC_PWM1->TCR = (1 << 0) | (1 << 3); // Start PWM
-
-    // === MAIN LOOP ===
     while(1)
     {
         read_key = 0xFF;
 
-        // Scan ROW-0 only
         for(col_idx = 0; col_idx < 4; col_idx++)
         {
             set_column(col_idx);
-            delay_ms(5);  // Short delay for stable reading
+            delay_ms(5);
 
             if(is_row0_pressed()) {
-                read_key = col_idx;  // Key 0, 1, 2, or 3
+                read_key = col_idx;
 
-                // Wait for key release
                 while(is_row0_pressed()) {
                     delay_ms(10);
                 }
@@ -128,22 +111,20 @@ int main(void)
             }
         }
 
-        // Restore columns
         LPC_GPIO2->FIOSET = COL_MASK_P2;
         LPC_GPIO0->FIOSET = COL_MASK_P0;
 
-        // Update brightness immediately on key press
         if(read_key != 0xFF && read_key != last_key) {
             last_key = read_key;
 
             switch(read_key) {
-                case 0: duty_cycle = 10;  break;  // 10%
+                case 0: duty_cycle = 10; break;
-                case 1: duty_cycle = 25;  break;  // 25%
+                case 1: duty_cycle = 25; break;
-                case 2: duty_cycle = 50;  break;  // 50%
+                case 2: duty_cycle = 50; break;
-                case 3: duty_cycle = 75;  break;  // 75%
+                case 3: duty_cycle = 75; break;
             }
         }
 
-        delay_ms(50);  // Main loop delay
+        delay_ms(50);
     }
 }