MAX7456.cpp

00001 #include "mbed.h"
00002 #include "MAX7456.h"
00003 
00004 namespace mbed {
00005 
00006 
00007 
00008 MAX7456::MAX7456(PinName mosi, PinName miso, PinName clk, PinName ncs, PinName nrst, const char* name)
00009         : Stream(name), _spi(mosi, miso, clk), _ncs(ncs), _nrst(nrst) {
00010                                 
00011 // initialisation code here
00012 
00013    _nrst = 0;   
00014    wait (0.5);   
00015    _nrst = 1;   
00016    wait (0.5);
00017 
00018    // Setup the spi for 8 bit data, high steady state clock,
00019    // second edge capture
00020    _spi.format(8,0);
00021 
00022    // 1MHz clock
00023    _spi.frequency(1000000);
00024 
00025 
00026 }
00027 
00028 
00029 
00030 
00031 void MAX7456::cls() {
00032     int tmp=0;
00033     tmp = _read(DMM);
00034     tmp &= 0xFB;
00035     _write(DMM,tmp);  //Make sure that DMM[2]=0 so that there can be write operations
00036 
00037     tmp = _read(DMM);
00038     tmp |= 0x04;
00039     _write (DMM,tmp);   //set DMM[2]=1 to clear all locations
00040 
00041     // should wait until DMM[2] goes back to zero, so we know the reset it finished
00042 
00043 }
00044 
00045 
00046 void MAX7456::locate(int x, int y) { //not sure if I understand the last line
00047     if ( (x<30) && (y<16) ) {
00048         int add = y*30+x; //formula for converting coordinates into denary location
00049         _write(DMAL,add);
00050         _write(DMAH,add>>8); // what does the ">>" mean?
00051     }
00052 }
00053 
00054 
00055 
00056 int MAX7456::_getc(int character) {
00057     for (int i = 0 ; i < 479 ; i++) { 
00058         int location= _read(DMDI,i)
00059         
00060         if((location == character - 0x30){ //characters from 1-9
00061             found= "true";
00062             }
00063         else if(location == character - 0x36){ // characters from A-Z
00064             found = "true";
00065             }
00066         else if(location == character - 0x3C){ // characters from a-z
00067             found = "true";
00068             }
00069         else if(location == character + 0x17){ //brackets ()
00070             found = "true";
00071             }    
00072         else{
00073             found = "false";
00074         
00075         if found = "true"{
00076             return(i);
00077             }
00078         else{
00079             return("character not found");
00080     }
00081 }
00082 
00083 
00084 int MAX7456::_putc(int c) {
00085     
00086     if((c >= 0x31)&&(c <= 0x39)) { //characters from 1-9
00087         c= c-0x30;
00088         }
00089     if((c >= 0x41)&&(c <= 0x5A)){ // characters from A-Z
00090         c= c-0x36;
00091         }
00092     if((c >= 0x61)&&(c <= 0x7A)){ // characters from a-z
00093         c= c-0x3C;
00094         }
00095     if((c == 0x28)&&(c == 0x29)){ //brackets ()
00096         c= c + 0x17;
00097         }    
00098     _write(DMDI,c);
00099     return(c);
00100 }
00101 
00102 
00103 
00104 
00105 void MAX7456::vtrim(int v) {
00106 }
00107 
00108 void MAX7456::htrim(int h) {
00109 }
00110 
00111 void MAX7456::format(char mode){
00112     if (mode == "P"){
00113         write(VM0,0x78);  // internal sync, OSD enable, PAL
00114         }
00115 }        
00116 
00117 int MAX7456::_read(int address) {
00118  // force bit 7 to 1 for a read
00119     address |= 0x80;
00120     _ncs=0; // select device
00121     _spi.write(address);          // send address
00122     int value = _spi.write(0x00); // send dummy
00123     _ncs=1; //deselect device
00124     return (value);
00125 }
00126 
00127 void MAX7456::_write(int address, int data) {
00128    // force bit 7 to 0 for a write
00129    address &= 0x7f;
00130    // select the device
00131    _ncs = 0;
00132    // write VM1    
00133    _spi.write(address); // send address
00134    _spi.write(data); // send some data
00135    // Deselect the device
00136    _ncs = 1; 
00137 }