Diff: xbee.cpp

Revision:

0:8f5379c94a69

Child:

3:37ea92feece2

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xbee.cpp	Sat Feb 11 20:47:45 2017 +0000
@@ -0,0 +1,106 @@
+#include "xbee.h"
+
+DigitalOut led_1(LED1);
+Mail<vector<char>, 30> received_messages;
+RawSerial xbee(p13, p14);
+const int FRAME_SPECIFIC_DATA_BEGIN[14] = {0x10, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFE, 0x00, 0x00};
+const int RECEIVE_PACKET_MESSAGE_START_INDEX = 15;
+
+const char START_DELIMITER = 0x7E;
+
+void send_message_via_xbee(const char* message, const int length)
+{
+    const vector<char> transmit_request = generate_transmit_request(message, length);
+    
+    for(int i=0; i<transmit_request.size(); i++)
+    {
+        xbee.putc(transmit_request[i]);
+    }
+}
+
+vector<char> generate_transmit_request(const char* message, const int length)
+{
+    vector<char> request;
+    
+    unsigned char checksum = 0xFF;
+    
+    request.push_back(START_DELIMITER);
+    
+    const uint16_t frame_length = 0x0E + length;
+    const uint8_t frame_length_msb = frame_length >> 8;
+    const uint8_t frame_length_lsb = (frame_length << 8) >> 8;
+    request.push_back(frame_length_msb);
+    request.push_back(frame_length_lsb);
+    
+    for(int i=0; i<14; i++)
+    {
+        request.push_back(FRAME_SPECIFIC_DATA_BEGIN[i]);
+        checksum -= FRAME_SPECIFIC_DATA_BEGIN[i];
+    }
+    
+    for(int i=0; i<length; i++)
+    {
+        request.push_back(message[i]);
+        checksum -= message[i];
+    }
+    
+    request.push_back(checksum);
+    
+    return request;
+}
+
+void read_frame()
+{
+    while(true)
+    {
+        while(xbee.getc() != 0x7E);
+        
+        vector<char> frame;
+        
+        frame.push_back(0x7E);
+        
+        const uint8_t frame_size_msb = xbee.getc();
+        const uint8_t frame_size_lsb = xbee.getc();
+        frame.push_back(frame_size_msb);
+        frame.push_back(frame_size_lsb);
+        const uint16_t frame_size = (frame_size_msb << 8) + frame_size_lsb;
+        
+        for(int i=0; i<frame_size + 1; i++)
+        {
+            frame.push_back(xbee.getc());
+        }
+            
+        vector<char> *parsed_frame = received_messages.alloc();
+        *parsed_frame = parse_receive_packet(frame);
+
+        received_messages.put(parsed_frame);
+    }
+}
+
+vector<char> parse_receive_packet(vector<char> transmitted_request)
+{    
+    vector<char>::const_iterator first = transmitted_request.begin() + RECEIVE_PACKET_MESSAGE_START_INDEX;
+    vector<char>::const_iterator last = transmitted_request.end() - 1;
+    vector<char> message(first, last);
+    return message;
+}
+
+void handle_message()
+{
+    while(true)
+    {
+        osEvent event = received_messages.get();
+        if (event.status == osEventMail) 
+        {
+            vector<char> *message = (vector<char>*)event.value.p;
+            
+            printf("Received message: ");
+            for(int i=0; i<message->size(); i++)
+            {
+                printf("%c", message->at(i));
+            }
+            printf("\r\n");
+            received_messages.free(message);
+        }
+    }
+}
\ No newline at end of file