I2C access when another master

[benri]

Hi, all

I hope someone can help me up.

The problem I have is:

PIC is the master device to access EEPROM, and we have another master device also access EEPROM. If I use CCS functions such as WRITE_EEPROM( ). How can I know another master not access EEPROM?

Can anyone give me examples to help me up?

Thanks.

Benri

[rnielsen]

This I2C bus is designed to have multiple Masters connected. There is a protocol that handles bus arbitration in case more than one Master tries to access the bus at the same time. If you have not read the I2C specification yet, I would strongly suggest that you do. There is some good information in that document. It is located at: http://www.semiconductors.philips.com/acrobat/literature/9398/39340011.pdf.

I suggest that you do your homework first (study specifications of hardware, software, research postings) before you start asking for help. Too many times people come here asking for help when they've not even tried to figure things out on their own first. Trial and error is also a good teacher. I remember more when I have to bang my head against the wall a few times while trying to figure out why my project doesn't work.

Also, the function write_eeprom() is used to access the 'Onboard' eeprom of the PIC. It doesn't access the I2C bus. You need to use the i2c_start(), i2c_write(), i2c_read() and i2c_stop() functions to access the I2C bus.

Ronald

[SherpaDoug]

I would connect the EEPROM to only one PIC. Have the second PIC ask the first PIC to fetch EEPROM data for it.
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