#: 20947 S12/OS9/68000 (OSK)
    11-May-95  18:24:45
Sb: #How to link I2C to OS-9
Fm: Martin Kreutzer 100020,2550
To: all

I have to port an OS-9 to a target system that has some devices
on a I2C-Bus (driven by a PCF8584).
Now I wonder what`s the "OS-9-like" way to link I2C to the System.

 I2C has commands like "write 2 bytes, then read 5 bytes answer"
 I see three ways to handle this:
 1) leave the I/O System alone and make a system-state module to
    handle I2C.
 2) use the I/O System. Delay write requests until I get the
    corresponding read request. I see some problems to keep
    the whole procedure atomic. Furthermore I think
    I have to write a new filemanager, because I need the sizes
    of the I/O requests in the device drivers.
 3) use the I/O System but handle the requests in SetStat calls.
    If I handle pure reads and writes with SetStats too, I can
    connect the device driver to a standard Filemanager (e.g. SCF).

 Right now I prefer Version 3 but I`m open to suggestions.
 Please give me your opinion..

Martin Kreutzer

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