why RTC mostly connected in i2c not spi

[bagavathi]

HI friends,

why mostly RTC is connect using i2c not in spi. whether it can be connet using spi or not?

 

[betwixt]

You can't use an SPI device on an I2C connection or the other way around. Even the number of wires is different. I2C is normally used because few designs use ONLY an RTC so making it share a bus with other I2C devices is preferable. In an SPI system you normally need individual select wires to each peripheral on the bus. There are SPI RTC devices and even one which falls somewhere between the two, the DS1302.

Brian.

 

[embpic]

and also may be reason that RTC will only update for second only. and speed which is required to transfer low count of byte is sufficient then why need spi and extra count of pins.

regars.