Revision 0:69d7ae72902c, committed 2016-10-11

Comitter:

Asoumy

Date:

Tue Oct 11 13:24:16 2016 +0000

Commit message:

RTC;

Changed in this revision

diff -r 000000000000 -r 69d7ae72902c ds1338.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ds1338.cpp	Tue Oct 11 13:24:16 2016 +0000
@@ -0,0 +1,111 @@
+#include "mbed.h"
+#include "ds1338.h"
+
+/*
+ * Constructor, initialize the ds1338 on i2c interface.
+ * @param sda : sda i2c pin (PinName)
+ * @param scl : scl i2c pin (PinName)
+*/
+DS1338::DS1338(PinName sda, PinName scl): _i2c(sda, scl) {
+    _i2c.frequency(400000);
+    buffer[0]=0x07;
+    _i2c.write(DS1338_ADR,buffer,1,true);
+    _i2c.read(DS1338_ADR,buffer,1);
+    if (buffer[0]&0x20){
+       buffer[0]=0x07;
+       buffer[1]=0xB0;//do not erase error condition !
+    }else{
+       buffer[0]=0x07;
+       buffer[1]=0x90;
+    }
+    _i2c.write(DS1338_ADR,buffer,1+1);
+}
+/**
+ * read bytes from nvram (55 bytes available)
+ * @param adr the start address (starts at 0)
+ * @param count number of byte to read
+ * @param data where to put the bytes
+ * @return the byte
+ */
+void DS1338::read(unsigned char adr,unsigned char count,char * data) {
+    if (count>DS1338_BUFFER_SIZE) {
+        count=DS1338_BUFFER_SIZE;
+    }
+    buffer[0]=9+adr;
+    _i2c.write(DS1338_ADR,&(buffer[0]),1,true);
+    _i2c.read(DS1338_ADR,data,count);
+}
+/**
+ * write bytes to nvram (55 bytes available)
+ * @param adr the start address (starts at 0)
+ * @param count number of byte to write
+ * @param data to be written
+ * @return the byte
+ */
+void DS1338::write(unsigned char adr,unsigned char count,char * data) {
+    if (count>DS1338_BUFFER_SIZE-1) {
+        count=DS1338_BUFFER_SIZE-1;
+    }
+    buffer[0]=9+adr;
+    for (unsigned char i=0; i<count; i++) {
+        buffer[1+i]=*(data+i);
+    }
+    _i2c.write(DS1338_ADR,buffer,1+count);
+}
+/**
+ * read the current time
+ * @param x the time;
+ */
+void DS1338::readTime(tm * time) {
+    buffer[0]=0;
+    _i2c.write(DS1338_ADR,&(buffer[0]),1,true);
+    _i2c.read(DS1338_ADR,buffer,9);
+    time->tm_sec=((buffer[0]>>4)&0x07)*10+(buffer[0]&0x0F);
+    time->tm_min=((buffer[1]>>4)&0x07)*10+(buffer[1]&0x0F);
+    time->tm_hour=((buffer[2]>>4)&0x03)*10+(buffer[2]&0x0F);
+    time->tm_mday=((buffer[4]>>4)&0x03)*10+(buffer[4]&0x0F);
+    time->tm_mon=((buffer[5]>>4)&0x01)*10+(buffer[5]&0x0F)-1;
+    time->tm_year=((buffer[6]>>4)&0x0F)*10+(buffer[6]&0x0F);
+    if (time->tm_year<70){
+       time->tm_year+=100;
+    }
+    time->tm_wday=buffer[3]&0x07;
+    time->tm_yday=0;
+    time->tm_isdst=0;
+    if (time->tm_sec>=60||
+        time->tm_min>=60||
+        time->tm_hour>=24||
+        time->tm_mday>31 || time->tm_mday<1||
+        time->tm_mon>11||
+        time->tm_wday>=7||
+        buffer[0x08]!=0xCA||//checksum
+        (buffer[0x07]&0x20)!=0){//error condition
+          time->tm_sec=0;
+          time->tm_min=0;
+          time->tm_hour=0;
+          time->tm_mday=1;
+          time->tm_mon=0;
+          time->tm_year=70;
+          time->tm_wday=1;
+          time->tm_yday=0;
+          time->tm_isdst=0;
+          writeTime(time);
+        }
+}
+/**
+ * write the current time
+ * @param time the time;
+ */
+void DS1338::writeTime(tm * time) {
+   buffer[0]=0;
+   buffer[1]=(((time->tm_sec/10)<<4)+(time->tm_sec%10))&0x7F;//clock not halted
+   buffer[2]=(((time->tm_min/10)<<4)+(time->tm_min%10))&0x7F;
+   buffer[3]=(((time->tm_hour/10)<<4)+(time->tm_hour%10))&0x3F;//mode 24h
+   buffer[4]=(time->tm_wday)&0x03;
+   buffer[5]=(((time->tm_mday/10)<<4)+(time->tm_mday%10))&0x3F;
+   buffer[6]=((((time->tm_mon+1)/10)<<4)+((time->tm_mon+1)%10))&0x1F;
+   buffer[7]=((((time->tm_year%100)/10)<<4)+(time->tm_year%10))&0xFF;
+   buffer[8]=0x90;//1Hz, erase error cond
+   buffer[9]=0xCA;
+   _i2c.write(DS1338_ADR,buffer,1+9);
+}

diff -r 000000000000 -r 69d7ae72902c ds1338.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ds1338.h	Tue Oct 11 13:24:16 2016 +0000
@@ -0,0 +1,51 @@
+#ifndef __EEPROM__H_
+#define __EEPROM__H_
+
+#include "mbed.h"
+
+#define DS1338_ADR     0xd0
+#define DS1338_BUFFER_SIZE 10
+
+
+/**
+ * class to use a DS1338 rtc
+ */
+class DS1338 {
+public:
+    /*
+     * Constructor, initialize the ds1338 on i2c interface.
+     * @param sda : sda i2c pin (PinName)
+     * @param scl : scl i2c pin (PinName)
+    */
+    DS1338(PinName sda, PinName scl);
+    /**
+     * read bytes
+     * @param adr the start address
+     * @param count number of byte to read
+     * @param data where to put the bytes
+     * @return the byte
+     */
+    void read(unsigned char adr,unsigned char count,char * data);
+    /**
+     * write bytes
+     * @param adr the start address
+     * @param count number of byte to write
+     * @param data to be written
+     * @return the byte
+     */
+    void write(unsigned char adr,unsigned char count,char * data);
+    /**
+     * read the current time
+     * @param x the time;
+     */
+    void readTime(tm * x);
+    /**
+     * read the current time
+     * @param x the time;
+     */
+    void writeTime(tm * x);
+private:
+    I2C _i2c;
+    char buffer[DS1338_BUFFER_SIZE];
+};
+#endif