about specification of the fast mode i2c signal transition.

[t-iishii]

Hi,

In datasheet of i.MX6(IMX6DQCEC.pdf) section 4.11.9, 

Minimal value of Fast mode transition time specificaton(IC10, IC11) has a capacitance value as a timing parameter.

  1) Is it a input parameter? (request by i.MX6)

  2) Why does it have capacitance value as a timing parameter?

  3) If external I2C device work more faster than minimal value of this parameter,

      what kind of problems do we encounter?

  4) Both standard mode and Fast mode have different parameter for each mode.

      It seems a i2c PHY request parameter for each mode.

      If so, standard speed transfer on Fast mode, which parameter it must use?

Best regards,

Ishii.

[Yuri]

Hello,

  Please look at my comments below.

1.

  I2C is a bus, therefore its specifications relates for all devices,

connected to the I2C bus : masters\slaves, input \output .

2.

  For open drain signals (I2C, in particular) rise / fall timings depend on

capacitance load.

3.

  Illegal data may be taken if violation of rise / fall timings specs take place.

4.

  I2C masters set mode during transfer. Each transfer should satisfy its mode

specs. No standard speed transfer for Fast mode.

http://www.nxp.com/documents/user_manual/UM10204.pdf 

Have a great day,
Yuri

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