usart.cpp

00001 #include "usart.h"
00002 
00003 Serial usart(USBTX, USBRX);
00004 
00005 char positionTemp[7];
00006 char position[6];
00007 bool instructionReceived = false;
00008 
00009 //serial interupt service function
00010 //ͨÐÅЭÒé£bpositionTemp = {0xff, ID, angle, 0xEE}
00011 // angle·¶Î§£º[0,180]£¬¶ÔÓ¦[-90, 90]
00012 typedef enum
00013 {
00014     CheckS,CheckW,Checka,Checkb,Checkc,Checkd,Checke,Checkf,CheckSum
00015 }STATE;
00016 
00017 void usart_ISR() {
00018         //if (usart.readable()) 
00019         {
00020             char data = usart.getc();
00021             //usart.printf("%d \n", data);
00022             static STATE State = CheckS;
00023             switch(State)
00024             {
00025                case CheckS:
00026                     if(data==0XFF) {
00027                         State=CheckW;
00028                         //usart.printf("receive S\n");
00029                         //instructionReceived = false;   
00030                     }   
00031                     else
00032                         State=CheckS;
00033                     break;
00034                case CheckW:
00035                     if(data==0XFE){
00036                         State=Checka;
00037                         //usart.printf("receive W\n");
00038                         }
00039                     else if(data==0XFF)
00040                         State=CheckW;
00041                     else 
00042                         State=CheckS;
00043                     break;
00044                 case Checka:
00045                     positionTemp[0]=data;
00046                     State=Checkb;
00047                     //usart.printf("receive pos 0 \n");
00048                     break;
00049                 case Checkb:
00050                     positionTemp[1]=data;
00051                     State=Checkc;
00052                     //usart.printf("receive pos 1 \n");                    
00053                     break;
00054                 case Checkc:
00055                     positionTemp[2]=data;
00056                     //usart.printf("receive pos 2 \n");
00057                     State=Checkd;
00058                     break;
00059                 case Checkd:
00060                     positionTemp[3]=data;
00061                      //usart.printf("receive pos 3 \n");
00062                    State=Checke;
00063                     break;
00064                 case Checke:
00065                     positionTemp[4]=data;
00066                     //usart.printf("receive pos 4 \n");
00067                     State=Checkf;
00068                     break;
00069                 case Checkf:
00070                     positionTemp[5]=data;
00071                     //usart.printf("receive pos 5 \n");
00072                     State=CheckSum;
00073                     break;
00074                 case CheckSum:
00075                     positionTemp[6]=data;
00076                     //usart.printf("receive sum \n");
00077                    //if(positionTemp[6]==(char)(positionTemp[0]+positionTemp[1]+positionTemp[2]+positionTemp[3]+positionTemp[4]+positionTemp[5]))
00078                         {
00079                             position[0]    = positionTemp[0];
00080                             position[1]    = positionTemp[1];
00081                             position[2]    = positionTemp[2];
00082                             position[3]    = positionTemp[3];
00083                             position[4]    = positionTemp[4];
00084                             position[5]    = positionTemp[5];
00085                             instructionReceived = true;
00086                         }
00087                     State=CheckS;
00088                     break;
00089                 default:
00090                     State=CheckS;
00091                     //instructionReceived = false;
00092                     break;
00093             }
00094 
00095         }
00096 }
00097 
00098 
00099 void usart_init(int baud) {
00100       usart.baud(baud);
00101     usart.attach(&usart_ISR);                                                           // attach serial interupt service function
00102     wait(1);
00103     //usart.printf("this is a testing code \n");
00104 }