RS422_put_.h

00001 /***************
00002 RS422 master libraly
00003 
00004 RS422 name(tx, rx)
00005 tx : mbed_tx
00006 rx : mbed_rx
00007 
00008 put(int id, float m1_duty, float m2_duty)
00009 id : 0 - 254
00010 duty : -1.0 - 1.0
00011 
00012 ****************/
00013 
00014 
00015 #define start_signal    0b11111111
00016 #define cool_time       0.0004
00017 
00018 class RS422
00019 {
00020 public :
00021     RS422(PinName mbed_tx, PinName mbed_rx) : Rs422(mbed_tx,mbed_rx) {
00022     }
00023 
00024     void begin(int baudrate) {
00025         Rs422.baud(baudrate);
00026         timer.attach(this, &RS422::put_time, cool_time);
00027     }
00028 
00029     void put(int id, float m1_duty, float m2_duty) {
00030         if (flag == 0) {
00031             ID = id;
00032             if (m1_duty < 0) {
00033                 m1_data = 0b10000000;
00034             } else {
00035                 m1_data = 0;
00036             }
00037             if (m2_duty < 0) {
00038                 m2_data = 0b10000000;
00039             } else {
00040                 m2_data = 0;
00041             }
00042             m1_data += fabs(m1_duty) * 100;
00043             m2_data += fabs(m2_duty) * 100;
00044 
00045             check_sum = (id + m1_data + m2_data) & 0b01111111;
00046         }
00047         flag = 1;
00048     }
00049 
00050 private :
00051     Serial Rs422;
00052     Ticker timer;
00053 
00054     short flag;
00055     int counter;
00056     int m1_data,m2_data,check_sum;
00057     int ID;
00058 
00059     void put_time() {
00060         switch (counter) {
00061             case 0 :
00062                 Rs422.putc(start_signal);
00063                 break;
00064             case 1 :
00065                 Rs422.putc(ID);
00066                 break;
00067             case 2 :
00068                 Rs422.putc(m1_data);
00069                 break;
00070             case 3 :
00071                 Rs422.putc(m2_data);
00072                 break;
00073             case 4 :
00074                 Rs422.putc(check_sum);
00075                 break;
00076             default :
00077                 break;
00078         }
00079         counter ++;
00080         if(counter >= 5) {
00081             counter = 0;
00082             flag = 0;
00083         }
00084     }
00085 };