Hi!

I was sending a mail about I2C firmware, but it was not completely sending
to PICList. That's way, I send again about it and the other problem.
Does anybody answer my questions?

1. What is "I2C firmware"?
2. When I2C-bus is used for the communication of a few devices, How long
bus-lengths can it be allowed?

Details are as follows:

< 1 >
I'm using 16F877, which is added new functional registers in the SSP.
I already successed to program Master-mode and Slave-mode by MPLAB.
Next, I'm trying to integrate MSSP modules. But i don't know about
firmware because i can't find the detail infomation in the Microchip
datasheet and the application note. I think about it that it is "Master
and Slave mode". But SSPADD register is a different value between Master
and Slave. How should i set the each value and be diverged each mode?

< 2 >
I investigated about I2C spec in Philips HP.
They wrote:
>"The number of ICs that can be connected to the same bus is
>limited only by a maximum bus capacitance of 400 pF."(p1,i2cbus_spec.pdf)

400pF? How method is it measured??
I want to know its length and type as a custom. The wire(or code?) must
be special type?

and they also wrote:

>"This is a lower-cost alternative for an RS-232C interface
>for connecting peripherals to a host computer via a simple 4-pin
>connector."(p3,i2cbus_spec.pdf)

Is it really?

Does anybody answer my questions?

Thanks in advance.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Shuji Hashimoto Laboratory.
      Waseda.Univ.Dept.of.Applied Physics.

   Keishiro Tabe    tab@shalab.phys.waseda.ac.jp

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