main.cpp

00001 #include "mbed.h"
00002 #include "TextLCD.h"
00003 
00004 SPI _spi(p5,p6,p7);                             //mosi, miso, sck
00005 DigitalOut cs(p8);                              // chip select of MCP3008
00006 TextLCD lcd(p24, p25, p26, p27, p28, p29, p30); // rs, rw, e, d0, d1, d2, d3
00007 
00008 
00009 int main() {
00010         int _data1;
00011         int _data2;
00012         cs=1;                       // deselect everything
00013         wait(0.001);
00014         _spi.format(8,0);           //see page1 of MCP3008 manual
00015         _spi.frequency(1000000);    //see page4 of MCP3008 manual
00016 
00017 //******************************************************************
00018 //    MCP3008 clock sequence and control bits
00019 //Once cs low, send start bit ==> 0x01  Not expecting any return
00020 //next, send control bits   Expecting return B9, B8
00021 //next, send anything, say 0x00, expecting return B7-B0
00022 //next shift B9,B8 left 8bits
00023 //next merge B9,B8 and B7-B0 to form 16bits data
00024 //next, mask off bit15-bit10, to get a clean 10 bit data
00025 //*******************************************************************
00026 
00027 //*******************************************************************
00028 //      1st 8bits         2nd 8bits           3rd 8bits
00029 //ch0      0x01              0x80                 0x00
00030 //ch1      0x01              0x90                 0x00
00031 //ch2      0x01              0xA0                 0x00
00032 //ch3      0x01              0xB0                 0x00
00033 //ch4      0x01              0xC0                 0x00
00034 //ch5      0x01              0xD0                 0x00
00035 //ch6      0x01              0xE0                 0x00
00036 //ch7      0x01              0xF0                 0x00
00037 //*******************************************************************
00038 
00039    
00040 
00041     while (1) {
00042 
00043 //ch0.
00044         cs=0;                               //cs low. start data collection
00045         _spi.write(0x01);                   //write start bit. Not expecting return
00046         _data1=_spi.write(0x80);            //write control bit, expecting return B9, B8
00047         _data2=_spi.write(0x00);            //write anything, expecting return B7-B0
00048         int ch0 =(_data1<<8) | _data2;          //merge two 8bits data becoming 16bits data
00049         ch0 = ch0 & 0x03FF;                 // mask off bit15 - bit10
00050         cs=1;                               //cs high. end of data collection
00051 
00052 //ch1   
00053         cs=0;                      
00054         _spi.write(0x01);
00055         _data1=_spi.write(0x90);
00056         _data2=_spi.write(0x00);
00057         int ch1 =(_data1<<8) | _data2;
00058         ch1 = ch1 & 0x03FF;
00059         cs=1;
00060 
00061 
00062 //ch2   
00063         cs=0;                      
00064         _spi.write(0x01);
00065         _data1=_spi.write(0xA0);
00066         _data2=_spi.write(0x00);
00067         int ch2 =(_data1<<8) | _data2;
00068         ch2 = ch2 & 0x03FF;
00069         cs=1;
00070 
00071 
00072 //ch3   
00073         cs=0;                      
00074         _spi.write(0x01);
00075         _data1=_spi.write(0xB0);
00076         _data2=_spi.write(0x00);
00077         int ch3 =(_data1<<8) | _data2;
00078         ch3 = ch3 & 0x03FF;
00079         cs=1;
00080 
00081 
00082 //ch4   
00083         cs=0;                      
00084         _spi.write(0x01);
00085         _data1=_spi.write(0xC0);
00086         _data2=_spi.write(0x00);
00087         int ch4 =(_data1<<8) | _data2;
00088         ch4 = ch4 & 0x03FF;
00089         cs=1;
00090 
00091 
00092 //ch5   
00093         cs=0;                      
00094         _spi.write(0x01);
00095         _data1=_spi.write(0xD0);
00096         _data2=_spi.write(0x00);
00097         int ch5 =(_data1<<8) | _data2;
00098         ch5 = ch5 & 0x03FF;
00099         cs=1;
00100 
00101 
00102 //ch6   
00103         cs=0;                      
00104         _spi.write(0x01);
00105         _data1=_spi.write(0xE0);
00106         _data2=_spi.write(0x00);
00107         int ch6 =(_data1<<8) | _data2;
00108         ch6 = ch6 & 0x03FF;
00109         cs=1;
00110 
00111 
00112 //ch7  
00113         cs=0;                      
00114         _spi.write(0x01);
00115         _data1=_spi.write(0xF0);
00116         _data2=_spi.write(0x00);
00117         int ch7 =(_data1<<8) | _data2;
00118         ch7 = ch7 & 0x03FF;
00119         cs=1;
00120 
00121 
00122 //Display the results
00123         lcd.cls();
00124         lcd.locate(0,0);
00125         lcd.printf("%d%d%d%d",ch0,ch1,ch2,ch3);
00126         lcd.locate(0,1);
00127         lcd.printf("%d%d%d%d",ch4,ch5,ch6,ch7);
00128 
00129         wait(0.01);
00130     }
00131 }
00132