Each I2C chip on a bus needs a unique(different) address. When you choose to use devices with fixed address you can only use 1 device of that type on a given buss, but you can combine it with other devices with other addresses.
For example, the clock chip you are looking at has a fixed address. Why would you want to use more then one clock chip? They keep real world time like 10:30AM, a second clock of this type would be redundant (useless, pointless).
But you might want to use that clock in conjunction with something like an EEPROM. As a rule these have several pins that allow you to alter the address so you can use several at a time. This makes sense because with memory more is better. So you could have one clock and up to 4 EEPROMs on the same bus.
There are two types of data transfers. Synchronous and Asynchronous. The I2C transfer is a synchronous transfer. The clock provided by the I2C master regulates the speed at which data bits are provided by the slave. The data rate is specified as a frequency of the clock provided to the slave by the master rather then as a baud rate.
It only seems to be contradictory due to either a language problem or perhaps a lack of needed previous knowledge on your part. I do not know which and it is very hard to tell as one may look like the other.
If you understand how Synchronous and Asynchronous transfers work and differ great. If not you need to start there prior to understanding I2C.
You could work on asking better formed questions. Provide links to the data sheets for the exact part or parts you are working with.
Some concepts are explained quite well by wikipedia. It is a good place to start if you need info.
I hope this has been helpful.
For example, the clock chip you are looking at has a fixed address. Why would you want to use more then one clock chip? They keep real world time like 10:30AM, a second clock of this type would be redundant (useless, pointless).
But you might want to use that clock in conjunction with something like an EEPROM. As a rule these have several pins that allow you to alter the address so you can use several at a time. This makes sense because with memory more is better. So you could have one clock and up to 4 EEPROMs on the same bus.
There are two types of data transfers. Synchronous and Asynchronous. The I2C transfer is a synchronous transfer. The clock provided by the I2C master regulates the speed at which data bits are provided by the slave. The data rate is specified as a frequency of the clock provided to the slave by the master rather then as a baud rate.
It only seems to be contradictory due to either a language problem or perhaps a lack of needed previous knowledge on your part. I do not know which and it is very hard to tell as one may look like the other.
If you understand how Synchronous and Asynchronous transfers work and differ great. If not you need to start there prior to understanding I2C.
You could work on asking better formed questions. Provide links to the data sheets for the exact part or parts you are working with.
Some concepts are explained quite well by wikipedia. It is a good place to start if you need info.
I hope this has been helpful.
simrantogether said: