Diff: PPMout.cpp

Revision:

0:04365c9c9994

Child:

1:9b1734761ce3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PPMout.cpp	Fri Sep 02 11:48:31 2016 +0000
@@ -0,0 +1,74 @@
+#include "PPMout.h"
+
+void PPMout::CMT_IRQHandler() {
+         
+     uint8_t tmp = CMT_MSC;  // reset interrupt
+     counter = (counter + 1)%ARRAY_SIZE;
+     CMT_CMD1 = (count_array[counter] >> 8) & 0xFF;
+     CMT_CMD2 = count_array[counter] & 0xFF;
+}
+
+PPMout::PPMout() {
+    
+    // Fill the count array with initial values
+    for (int i = 0; i < CHANNELS; i++) {
+
+        count_array[i] = (int) (RANGE_STEPS*0.5 + ZERO_STEPS);
+    }
+
+    set_sync_length();
+    init();
+}
+
+void PPMout::update_channel(int channel, float value) {
+    
+    // Constrain value between 0 and 1
+    value = PIN(value, 0, 1);
+
+    // Constrain channel
+    channel = PIN(channel, 0, (CHANNELS-1));
+
+    // Calculate new step value
+    int steps = (int) (RANGE_STEPS*value + ZERO_STEPS);
+
+    // Insert new value into array
+    count_array[channel] = steps;
+
+    set_sync_length();
+}
+    
+void PPMout::init() {
+    
+    SIM_SCGC4 |= (1 << SIM_SCGC4_CMT_SHIFT);
+    SIM_SOPT2 |= (1 << SIM_SOPT2_PTD7PAD_SHIFT);   // drive strength
+    SIM_SCGC5 |= (1 << SIM_SCGC5_PORTD_SHIFT);  // power PORTD
+    PORTD_PCR7 = PORT_PCR_MUX(2)|(1<< PORT_PCR_DSE_SHIFT)|(1 << PORT_PCR_SRE_SHIFT);
+    CMT_PPS = CMT_PPS_VAL;    // 5 mhz
+    CMT_CGH1 = 1;
+    CMT_CGL1 = 1;
+    CMT_CMD1 = (count_array[counter] >> 8) & 0xFF;
+    CMT_CMD2 = count_array[counter] & 0xFF;
+    CMT_CMD3 = (GAP_STEPS >> 8) & 0xFF;
+    CMT_CMD4 = GAP_STEPS & 0xFF;
+    CMT_OC = 0x60;     // enable IRO
+    CMT_MSC = (1 << 3) | (1 << 1) | (1 << 0);     // enable CMT, interrupt and baseband
+    
+    NVIC_SetVector(CMT_IRQn, (uint32_t) &PPMout::CMT_IRQHandler);
+    NVIC_EnableIRQ(CMT_IRQn);
+}
+
+void PPMout::set_sync_length() {
+
+    int total = 0;
+
+    for (int i = 0; i < CHANNELS; i++) {
+
+        total += count_array[i];
+    }
+
+    // Update sync length to ensure it lasts 20ms
+    count_array[CHANNELS] = MAX_NON_GAP_STEPS - total;
+}
+
+int PPMout::count_array[ARRAY_SIZE] = {};
+int PPMout::counter = 0;
\ No newline at end of file