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I2C time and frequency ????

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darlling5147

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i2c data hold

may anyone can tell me how the freq of I2C in a IC to be set?
for example the datasheet attached below. (red circled data)

the to come out the value of those I2C frequency and time?



 

darlling5147

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baud rate vs frequency in i2c

really no ppl can help me? it is really urgent for me since i need to present it nx week tuesday....


HELP !!!!
 

joby16

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Hi,

If you are using the I2C module, set the baud rate < 400Khz by configuring the registers... If you are writing the driver, set the frequency by adjusting the time delay......
 

darlling5147

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so why the I2C freq. cannot be 3.5Mbps? cant we make it to high-speed mode?
how to set the data hold and setup time?
how to set the delay time too?
[/img]
 

jiang

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Because of electrical characteristic, most IC vendors define max I2C frequency up to 400KHz, even only 100KHz.
I don't see any IC vendor able to support 3.5Mbps I2C spec.
If you have high speed communication requests, you can try SPI interface.

I don't understand about how to set data setup/hold time and delay time.
Actually you don't detail your question and your application so that no body can answer correctly.
Do you write the firmware for microcontroller??
Or do you design a ASIC for something??
 

darlling5147

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jiang said:
Because of electrical characteristic, most IC vendors define max I2C frequency up to 400KHz, even only 100KHz.
I don't see any IC vendor able to support 3.5Mbps I2C spec.
If you have high speed communication requests, you can try SPI interface.

I don't understand about how to set data setup/hold time and delay time.
Actually you don't detail your question and your application so that no body can answer correctly.
Do you write the firmware for microcontroller??
Or do you design a ASIC for something??
actually i dun design anything by using I2C, i jus wanna understand how the time and freq been set which stated in every datasheet (as i attached above) .

in the datasheet, there are a colum that specified the I2C data setup time and data hold time in nsecond. i just wonder how the designer stated down the value. is they using any formula to calculate out the value?

I am very very new to I2C, I wanna descover more on it. It might have stupid Q come out from me but hope u guys wont angry ya :D
 

jiang

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If your microcontroller is embedded with I2C i/f, you just need to check that the target device timing spec meets your microcontroller timing spec or not.
Most microcontroller embedded I2C i/f is just only set the I2C master/slave and freq.

If I2C protocal is done by software, you can determine the freq and setup/hold time, of course.
But you still need to meet the target device timing.
 

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