Diff: main.cpp

Revision:

0:050184ab5c0d

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Tue Sep 02 08:20:13 2014 +0000
@@ -0,0 +1,131 @@
+#include "mbed.h"
+#include "FastIO.h"
+#include "FastPWM.h"
+
+FastOut<LED1> led;
+
+//Pin 29 and 30 are connected to pin 21
+FastIn<p29> CAP_2_1_input;
+FastIn<p30> CAP_2_0_input;
+FastPWM pwm(p21);
+
+
+Serial pc(USBTX, USBRX); // tx, rx
+
+#define TIM2CR0 LPC_TIM2->CR0
+#define TIM2CR1 LPC_TIM2->CR1
+
+//void _cap_2_1_falling() {
+  //  pc.printf("Interrupt: %X\n", LPC_TIM2->IR);
+    //led = 1;
+//}
+
+int main()
+{
+    
+    unsigned int ticks = 226;
+    
+    // This signal should give a manchester encoded 101010101
+    pwm.period_ticks(ticks);
+    pwm.pulsewidth_ticks(ticks / 2);
+    
+    // Setup TIM2
+    
+    // SC
+    LPC_SC->PCONP |= (1<<22);               // Power on the Timer2
+    LPC_SC->PCLKSEL1 &= ~(3<<12);           // Select CCLK/4 for TIM2 (whipes previous clock setting)
+    LPC_SC->PCLKSEL1 |= (1<<12);            // Select CCLK for TIM2
+    
+    // CCR
+    LPC_TIM2->CCR |= (3 << 1);  // Set CAP2.0 on falling edge with interrupt
+    LPC_TIM2->CCR |= (1 << 3);  // Set CAP2.1 on rising edge
+       
+    pc.printf("CCR: %X\n", LPC_TIM2->CCR);
+
+    // TCR
+    LPC_TIM2->TCR = 0x0002;                  // Reset TIM2
+    LPC_TIM2->TCR = 0x0001;                  // Enable TIM2
+    
+    bool buffer [16];
+    int bits = 0;
+        
+    //NVIC_DisableIRQ(TIMER2_IRQn);
+    //NVIC_SetVector(TIMER2_IRQn, (uint32_t)&_cap_2_1_falling);
+    //NVIC_EnableIRQ(TIMER2_IRQn);
+    
+    while(1) {        
+        
+        //pc.printf("Interrupt: %X\n", LPC_TIM2->IR);
+
+        // Poll CRO (falling edge) intterupt
+        if (LPC_TIM2->IR & (1 << 4)) {
+            
+            led = 1;
+            
+            wait(100);
+            
+            led = 0;
+            
+            int diff = (TIM2CR0 - TIM2CR1) % 0xFFFFFFFF;
+            
+            if (diff > 90 && diff < 136) {          // Check if diff is equal to T=1/848kHz with 20% error
+                // bit transition                
+
+                if (bits == 0) {                     // Start of sequence
+                    buffer[0] = 1;
+                } else {
+                    buffer[bits] = !buffer[bits-1];
+                }
+                
+                pc.printf("Trasition: %u\n", diff);
+                
+            } else if (diff > 45 && diff < 68) {    // Check if diff is equal to T/2
+                // repeat last bit
+                
+                if (bits == 0) {                     // Start of sequence
+                    buffer[0] = 1;
+                } else {
+                    buffer[bits] = buffer[bits-1];
+                }
+                
+                pc.printf("Repeat: %u\n", diff);
+
+            } else {
+                // error, default to 1 
+                pc.printf("Error: %u\n", diff);
+            }
+            
+            bits = bits + 1 % 16;
+            
+            LPC_TIM2->IR |= (1 << 4);               // Clear IR by writing a one
+                     
+        }
+        
+//        if (bits == 0) {
+//            
+//            for (int i = 0; i< 16; i++) {
+//                pc.printf("%u", (int) buffer[i]);
+//            }
+//            
+//            pc.printf("\n");
+//
+//        }
+        
+//        // Poll CRO (rising edge) intterupt
+//        if (LCP_TIM2-IR != (1 << 5)) {
+//            
+//            int diff = (TIM2CR1 - TIM2CR2) % 0xFFFFFFFF;
+//
+//            // Do checks
+//            
+//            // End checks
+//            
+//            
+//            LCP_TIM2->IR &= ~(1 << 5);
+//        }
+                
+    
+    
+    }
+    
+}