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--- ds1307_how_to_access_ram [2011/09/12 21:39] – tomgee
+++ ds1307_how_to_access_ram [2011/09/12 21:44] (current) – tomgee
@@ Line 3: / Line 3: @@
 The Ram on the device starts at address 0x08. The first 7 locations are the RTC.\\
-{{:rtc_registers.jpg?400|}}
+{{:rtc_registers.jpg?600|}}
+To get to the start of RAM, use the following code:
+     Wire.beginTransmission(DS1307_ADDRESS);
+     Wire.send(8);
+     Wire.endTransmission();
+This will set the I2C address to 0x68, the DS1307 Address.\\
+The second line sets the register index to 8, the start of RAM.\\
+The third line, Wire.endTransmission(); , transmits the sequence.\\
+Subsequent reads from the chip will start at 8. For example, to read 4 bytes from the chip:\\
+     Wire.requestFrom(DS1307_ADDRESS, 4);
+The above line will put the 4 bytes into the receive buffer. To fetch the bytes:
+     while(Wire.available())    // slave may send less than requested
+     {
+      byte c = Wire.receive(); // receive a byte as character
+      Serial.print(c, HEX);         // print the character
+      Serial.print(" ");
+     }