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 void MAX7456::cls() {
00031     int tmp=0;
00032     tmp = _read(DMM);
00033     tmp &= 0xFB;
00034     _write(DMM,tmp);  //Make sure that DMM[2]=0 so that there can be write operations
00035 
00036     tmp = _read(DMM);
00037     tmp |= 0x04;
00038     _write (DMM,tmp);   //set DMM[2]=1 to clear all locations
00039 
00040     // should wait until DMM[2] goes back to zero, so we know the reset it finished
00041 
00042 }
00043 
00044 
00045 void MAX7456::locate(int x, int y) { //not sure if I understand the last line
00046     if ( (x<30) && (y<16) ) {
00047         int add = y*30+x; //formula for converting coordinates into denary location
00048         _write(DMAL,add);
00049         _write(DMAH,add>>8); // what does the ">>" mean?
00050     }
00051 }
00052 
00053 
00054 
00055 int MAX7456::_getc() {
00056     return(0);
00057 }
00058 
00059 
00060 int MAX7456::_putc(int c) {
00061 
00062     if ((c >= 0x31)&&(c <= 0x39)) { //characters from 1-9
00063         c= c-0x30;
00064     } else if ((c >= 0x41)&&(c <= 0x5A)) { // characters from A-Z
00065         c= c-0x36;
00066     } else if ((c >= 0x61)&&(c <= 0x7A)) { // characters from a-z
00067         c= c-0x3C;
00068     } else if ((c == 0x28)&&(c == 0x29)) { //brackets ()
00069         c= c + 0x17;
00070     }
00071 
00072     _write(DMDI,c);
00073 
00074     return(c);
00075 }
00076 
00077 
00078 
00079 
00080 void MAX7456::vtrim(int v) {
00081 }
00082 
00083 void MAX7456::htrim(int h) {
00084 }
00085 
00086 
00087 void MAX7456::format (char mode) {
00088 
00089     if (mode == 'P') {
00090         write(VM0,0x78);  // PAL
00091     } else if (mode == 'N') {
00092         write(VM0,0x78);  // NTSC
00093     }
00094     
00095 }
00096 
00097 int MAX7456::_read(int address) {
00098 // force bit 7 to 1 for a read
00099     address |= 0x80;
00100     _ncs=0; // select device
00101     _spi.write(address);          // send address
00102     int value = _spi.write(0x00); // send dummy
00103     _ncs=1; //deselect device
00104     return (value);
00105 }
00106 
00107 void MAX7456::_write(int address, int data) {
00108     // force bit 7 to 0 for a write
00109     address &= 0x7f;
00110     // select the device
00111     _ncs = 0;
00112     // write VM1
00113     _spi.write(address); // send address
00114     _spi.write(data); // send some data
00115     // Deselect the device
00116     _ncs = 1;
00117 }
00118 
00119 }