Echelon I/O Model Reference for Smart Transceivers and Neuron Chips - Manual (Page 93)

I/O Model Reference 83
For I 2 C input/output, io_in( ) and io_out( ) return a 0 or 1 value reflecting the fail
(0) or pass (1) status of the transfer. A failed status indicates that the addressed
device did not acknowledge positively on the bus, or that the SCL was low at the
start of the transfer.
For more information on this protocol and the devices that it supports, see
documentation for Philips Semiconductors Microcontroller Products, under I
2 C
bus descriptions. This I/O model implementation was modified for Neuron C
Version 2.1. To use the previous implementation (in case of modification to
existing applications where the previous implementation is required for memory
considerations) use the #pragma codegen use_i2c_version_1 compiler directive.
See the
Neuron C Reference Guide for information about this pragma. If you use
the Version 1 i2c model, you must use pin IO_8 and you cannot use any
modifiers.
Syntax
pin i2c [use_stop_condition] [__slow] [__fast] io-object-name ;
pin
Specify pin IO_0 or IO_8. The i2c model requires pins IO_0 and IO_1, or
IO_8 and IO_9.
use_stop_condition
Optionally specifies that data transfers should be repeated until a stop
condition is reached. A stop condition is defined as a change in the state of
the data line (SDA), from LOW to HIGH, while the clock line (SCL) is HIGH.
__slow
Optionally specifies that the I 2 C bus should use the standard mode of 100
kbps. This mode is the default if no mode is specified. Mutually exclusive
with __fast.
__fast
Optionally specifies that the I 2 C bus should use the fast mode of 400 kbps.
Mutually exclusive with __slow.
io-object-name
A user-specified name for the I/O object, in the ANSI C format for variable
identifiers.
Usage
boolean return-value ;
unsigned int data-buffer [ buffer-size ];
unsigned int dev-address , count ;
// i2c I/O object without the stop condition specified (stop assumed)
return - value = io_in( io - object - name , data - buffer , dev - address , count );
return - value = io_out( io - object - name , data - buffer , dev - address , count );