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microcontrollers communicating

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mdeepamenon

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two microcontrollers with different clock frequency have to communicate with each other using the I2C protocol. what will be the clock frequency adopted by the system?
 

Hi mdeepamenon

If you read the I²C specification you will see that the Clock Synchronisation procedure will 'slow down' the faster clock to suit the speed of the slower clock in any single transmission. This is designed to enable slow and fast devices to communicate on the same I²C bus. See Philips I²C Specification section 8.1.

Philips I²C Spec. Jan 2000 (39340011.pdf):
**broken link removed**

You may find this easier reading
http://www.esacademy.com/faq/i2c/


happy reading ... Polymath
 
hello friend don't you think a serial communication(rs232) mode is enough to communicate between two µc. as far as i know it is very simple to use this technique than any other one
 

I prefer to use SPI than serial if i want to make a communication for two microcorntrollers although it needs more pin than serial. I suggest you to using SPI.
 

Hi rooftop,

Why do you prefer SPI than Serial communincation (RS-232)? i think you would give us some explanation for your preference, for sure we will appreciate it alot.
 

I prefer SPI because it's not depend on the baudrate, setting the baud rate is a complex one if you don't have a match xtal but with spy you just need to see specification of your microcontroller and it's easy if you have a same microcontroller.And in my opinion there's a lot of microcontroller with SPI integrated in it now so that makes the setup easier.

That's my preference please any feedback if i'm wrong.

Best Regards
 

deepu_ttc said:
hello friend don't you think a serial communication(rs232) mode is enough to communicate between two µc. as far as i know it is very simple to use this technique than any other one
Click to expand...
This is a very slow way of c.o.m.m.u.n.i.c.a.t.i.n.g.

Rooftop said:
I prefer SPI because it's not depend on the baudrate..........
Click to expand...

What do you think BAUD RATE means? Baud Rate = Bits/second.
SPI Baud rate is not normally quoted but depends upon the Master Clock Rate. You have to set the Baud Rate in SPI - indirectly - by setting to clock speed.

I²C has a baud rate - generally slower than SPI - again set by the clock rate - but as a slower device can slow down a faster one the baud rate is negotiated between them.

regards ... Polymath
 

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