PeMod_ZPH01.cpp

00001 #include "SysConfig.h"
00002 
00003 #define ZPH01_CMD_LEN   0
00004 #define ZPH01_DAT_LEN   9
00005 #define ZPH01_GAS_ID    0x18
00006 
00007 #define uart_zph01 uart_sen
00008 //#define uart_db uart_pc
00009 
00010 int ZPH01_Init(void)
00011 {    
00012     return 0;    
00013 }
00014 
00015 float ZPH01_ReadPM25(void)
00016 {
00017     int tmp, sum, i;
00018     uint8_t data[ZPH01_DAT_LEN];
00019                    
00020     #if defined uart_db
00021     uart_db.printf("\n\rZPH01 return ");
00022     #endif
00023     
00024     do{
00025         while(!uart_zph01.readable());
00026         
00027         tmp = uart_zph01.getc();
00028         #if defined uart_db
00029         uart_db.printf("0x%02X ", tmp);
00030         #endif
00031     }while(tmp != 0xFF);
00032     data[0] = 0xFF;
00033     
00034     do{
00035         while(!uart_zph01.readable());
00036         tmp = uart_zph01.getc();
00037         #if defined uart_db
00038         uart_db.printf("0x%02X ", tmp);
00039         #endif
00040     }while(tmp != ZPH01_GAS_ID);
00041     data[1] = ZPH01_GAS_ID;
00042                
00043     for(i=2; i<ZPH01_DAT_LEN; i++)
00044     {        
00045         data[i] = uart_zph01.getc();
00046         #if defined uart_db
00047         uart_db.printf("0x%02X ", data[i]);
00048         #endif
00049     }    
00050     
00051     #if defined uart_db
00052     uart_db.printf(".\n\r");
00053     #endif
00054     
00055     sum = ZPH01_CalCheckSum(data);
00056     if(data[ZPH01_DAT_LEN - 1] == sum)
00057     {
00058         //Unit: percents(%)
00059         float ratioPM25 = data[3] * 1.0 + data[4] / 100.0;
00060         #if defined uart_db
00061         uart_db.printf("PM2.5 PWM ratio is %f%%.\n\r", ratioPM25);
00062         #endif
00063         //Unit: ug/m^3
00064         float volPM25 = ratioPM25 * 20.43;
00065         return volPM25;
00066     }
00067     else
00068     {
00069         #if defined uart_db
00070         uart_db.printf("Incorrect checksum 0x%02X, expect 0x%02X.\n\r", sum, data[ZPH01_DAT_LEN - 1]);
00071         #endif
00072         return -1;
00073     }
00074 }
00075 
00076 uint8_t ZPH01_CalCheckSum(uint8_t *packet)
00077 {
00078     uint8_t i, checksum = 0;
00079     for( i = 1; i < 8; i++)
00080     {
00081         checksum += packet[i];
00082     }
00083     checksum = 0xff - checksum;
00084     checksum += 1;
00085     return checksum;
00086 }