DS 1307 Real time Clock interface with Intel 386EX processor

I don't think there's any hardware reason why you couldn't do that and drive the I2C protocol via pure software. I assume you mean regular digital I/O pins and not to anything like a UART.

I am using parallel I/O ports available in the processor. Do I need pullup resistors to hook SCl and SDA to processor? I am new to this field and any help will be appreciated.

Thanks

What might be a problem is the open-drain nature (wire-and) of the I2C bus. On many I/O ports, you'll need three-state buffers and send the data via the output enable pin to simulate an open-drain device.

If the output bits are easily individually controlled as inputs or outputs, the same effect can be created using the data direction register as the outputs and pre-set the output register bits to zeroes.

You have to create the bus sequences bit by bit in software.

HTH

Tauno Voipio tauno voipio @ iki fi

I'm not a hardware guy but it looks like you do need pullup resistors on both lines. You might try getting a book like "Designing Embedded Hardware".

In article , Gary Kato writes

SCL and SDA lines do need pullups, stick a 4K7 up to the positive supply on each one. Even if the processor already has pullups it won't do any harm