EEprom Attachment and I2C

James Long

Ok...so I'm looking at the connections for the Eeprom and the Propclip/plug.

I'm wondering why the SCL line doesn't have a pull up resistor on it.

Now the question. If it did will that cause problems.......also can the eeprom be on a bus with other I2C components?

I'm not planning on using the standard eeprom but rather the 512k size from microchip.

Anyone with experience with this can help me out.

James L

Phil Pilgrim (PhiPi)

The SCL line doesn't need a pullup, and can be driven both high and low, unless one of the following conditions holds:

1. There is more than one master on the bus. (The Propeller is usually the sole master device, possibly driving multiple slaves, such as EEPROMs, sensors, etc.)

2. There are slow slave devices on the bus that hold SCL low to pace the transfer of data. (This is likely not the case for most EEPROMS.)

-Phil

Post Edited (Phil Pilgrim (PhiPi)) : 11/3/2006 11:32:35 PM GMT

James Long

Phil,

Ok so the prop can drive the clock line.....what about other I2C parts on the same line?



James L

Chris Savage

James,
·
·· Phil hinted at it, but yes, you can have multiple devices on the bus, provided no others are a master and that none assert the SCL line.· Take care.

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Chris Savage
Parallax Tech Support

James Long

Chris,

I was just worried because the Propeller loads it's startup information from the eeprom, I was concerned this·may interfere.

The propeller would be the only master.

Thanks for the answers.

James L

Chris Savage

James,
·
·· Different devices on the bus would have different addresses, so there shouldn’t be a problem.· Take care.

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Chris Savage
Parallax Tech Support