DS1307 < Embedded_Systems

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---+ !I2C Real Time Clock and serial EEPROM

While our Raspberry Pi is usually connected to the network from which it can get date and time, other micro-controllers (the Arduinio is an example) do not necessarily have an Ethernet connection. Also out Raspberry may run temporarily without network connection. In order to know date and time also in these cases there is the DS1307 Real Time Clock (RTC), which can be programmed through I2C and which can keep date and time through a 32.768 kHz oscillator running on a 3 V battery. Date and time is stored in 56 bytes of battery backed RAM memory.

The PCB also includes an !AT24C32 !I2C serial EEPROM onto which 4 kByte (32 kbits) of data may be stored. Since it is rather simple to access the EEPROM through the !I2C bus we will use this device to collect experience in !I2C programming. A top secret message has been programmed into the chip, which the student detectives are asked to discover.

The PCB also has provisions to mount a ds18b20 digital thermometer, which on our boards however is not mounted.
| <img alt="rtcfront.png" height="332" src="%ATTACHURL%/rtcfront.png" title="rtcfront.png" width="338" /> | <img alt="rtcback.png" height="325" src="%ATTACHURL%/rtcback.png" title="rtcback.png" width="345" /> |
| RTC module front | RTC module back with battery |
As you can see, the !I2C connections exist twice on the board, only one of which is needed to run the board.

-- %USERSIG{UliRaich - 2017-02-01}%

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Topic attachments
I	Attachment	History	Action	Size	Date	Who	Comment
png	rtcback.png	r1	manage	774.8 K	2017-02-01 - 14:17	UnknownUser
png	rtcfront.png	r1	manage	2290.3 K	2017-02-01 - 14:17	UnknownUser

Topic revision: r2 - 2017-02-01 - uli