This project demonstrates how to interface with the 24C02 EEPROM using a software-based I2C driver. The task involves reading and writing data to/from the EEPROM, implementing a 1-second counter, and preserving the counter value across system resets.
- First, study the datasheet of the EEPROM IC 24C02: 24C02 Datasheet.
- This will provide you with detailed information on how to interact with the EEPROM, its specifications, timing requirements, and communication protocol.
- Implement a software-based I2C driver to communicate with the 24C02 EEPROM.
- The driver should be able to:
- Read data from EEPROM.
- Write data to EEPROM.
- Create an 8-bit counter that increments every 1 second.
- Save the counter value to the EEPROM after each second.
- Display the current counter value on a seven-segment display.
- On system startup, load the counter value from the EEPROM to ensure it is restored after resets.
- An unwritten memory location in the EEPROM holds the value
0xFF(255). This can be used to check if the EEPROM is fresh or if the counter value is legitimate.
- An unwritten memory location in the EEPROM holds the value
- EEPROMs have limited write cycles. Writing too frequently can wear out the EEPROM.
- Refer to the EEPROM's datasheet to determine the number of write cycles supported by the device.
- Calculate the delay between writes to ensure that the EEPROM will last at least 10 years.
- Adjust the counter so that it writes to EEPROM at intervals that align with this goal.
- Extend the previous implementation to handle a 32-bit (4 bytes) counter.
- Use 4 adjacent memory locations in the EEPROM to store the 32-bit counter value.
- To handle 32-bit data:
- Use bitwise shifts (
>>,<<) and bitwise OR (|) to assemble a 4-byte value from individual bytes. - Similarly, use bitwise shifts and AND (
&) operators to separate the 4-byte value into individual bytes.
- Use bitwise shifts (