ds1338.cpp

00001 #include "mbed.h"
00002 #include "ds1338.h"
00003 
00004 /*
00005  * Constructor, initialize the ds1338 on i2c interface.
00006  * @param sda : sda i2c pin (PinName)
00007  * @param scl : scl i2c pin (PinName)
00008 */
00009 DS1338::DS1338(PinName sda, PinName scl): _i2c(sda, scl) {
00010     _i2c.frequency(400000);
00011     buffer[0]=0x07;
00012     _i2c.write(DS1338_ADR,buffer,1,true);
00013     _i2c.read(DS1338_ADR,buffer,1);
00014     if (buffer[0]&0x20){
00015        buffer[0]=0x07;
00016        buffer[1]=0xB0;//do not erase error condition !
00017     }else{
00018        buffer[0]=0x07;
00019        buffer[1]=0x90;
00020     }
00021     _i2c.write(DS1338_ADR,buffer,1+1);
00022 }
00023 /**
00024  * read bytes from nvram (55 bytes available)
00025  * @param adr the start address (starts at 0)
00026  * @param count number of byte to read
00027  * @param data where to put the bytes
00028  * @return the byte
00029  */
00030 void DS1338::read(unsigned char adr,unsigned char count,char * data) {
00031     if (count>DS1338_BUFFER_SIZE) {
00032         count=DS1338_BUFFER_SIZE;
00033     }
00034     buffer[0]=9+adr;
00035     _i2c.write(DS1338_ADR,&(buffer[0]),1,true);
00036     _i2c.read(DS1338_ADR,data,count);
00037 }
00038 /**
00039  * write bytes to nvram (55 bytes available)
00040  * @param adr the start address (starts at 0)
00041  * @param count number of byte to write
00042  * @param data to be written
00043  * @return the byte
00044  */
00045 void DS1338::write(unsigned char adr,unsigned char count,char * data) {
00046     if (count>DS1338_BUFFER_SIZE-1) {
00047         count=DS1338_BUFFER_SIZE-1;
00048     }
00049     buffer[0]=9+adr;
00050     for (unsigned char i=0; i<count; i++) {
00051         buffer[1+i]=*(data+i);
00052     }
00053     _i2c.write(DS1338_ADR,buffer,1+count);
00054 }
00055 /**
00056  * read the current time
00057  * @param x the time;
00058  */
00059 void DS1338::readTime(tm * time) {
00060     buffer[0]=0;
00061     _i2c.write(DS1338_ADR,&(buffer[0]),1,true);
00062     _i2c.read(DS1338_ADR,buffer,9);
00063     time->tm_sec=((buffer[0]>>4)&0x07)*10+(buffer[0]&0x0F);
00064     time->tm_min=((buffer[1]>>4)&0x07)*10+(buffer[1]&0x0F);
00065     time->tm_hour=((buffer[2]>>4)&0x03)*10+(buffer[2]&0x0F);
00066     time->tm_mday=((buffer[4]>>4)&0x03)*10+(buffer[4]&0x0F);
00067     time->tm_mon=((buffer[5]>>4)&0x01)*10+(buffer[5]&0x0F)-1;
00068     time->tm_year=((buffer[6]>>4)&0x0F)*10+(buffer[6]&0x0F);
00069     if (time->tm_year<70){
00070        time->tm_year+=100;
00071     }
00072     time->tm_wday=buffer[3]&0x07;
00073     time->tm_yday=0;
00074     time->tm_isdst=0;
00075     if (time->tm_sec>=60||
00076         time->tm_min>=60||
00077         time->tm_hour>=24||
00078         time->tm_mday>31 || time->tm_mday<1||
00079         time->tm_mon>11||
00080         time->tm_wday>=7||
00081         buffer[0x08]!=0xCA||//checksum
00082         (buffer[0x07]&0x20)!=0){//error condition
00083           time->tm_sec=0;
00084           time->tm_min=0;
00085           time->tm_hour=0;
00086           time->tm_mday=1;
00087           time->tm_mon=0;
00088           time->tm_year=70;
00089           time->tm_wday=1;
00090           time->tm_yday=0;
00091           time->tm_isdst=0;
00092           writeTime(time);
00093         }
00094 }
00095 /**
00096  * write the current time
00097  * @param time the time;
00098  */
00099 void DS1338::writeTime(tm * time) {
00100    buffer[0]=0;
00101    buffer[1]=(((time->tm_sec/10)<<4)+(time->tm_sec%10))&0x7F;//clock not halted
00102    buffer[2]=(((time->tm_min/10)<<4)+(time->tm_min%10))&0x7F;
00103    buffer[3]=(((time->tm_hour/10)<<4)+(time->tm_hour%10))&0x3F;//mode 24h
00104    buffer[4]=(time->tm_wday)&0x03;
00105    buffer[5]=(((time->tm_mday/10)<<4)+(time->tm_mday%10))&0x3F;
00106    buffer[6]=((((time->tm_mon+1)/10)<<4)+((time->tm_mon+1)%10))&0x1F;
00107    buffer[7]=((((time->tm_year%100)/10)<<4)+(time->tm_year%10))&0xFF;
00108    buffer[8]=0x90;//1Hz, erase error cond
00109    buffer[9]=0xCA;
00110    _i2c.write(DS1338_ADR,buffer,1+9);
00111 }