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CMC TECHNICAL REFERENCE MANUAL
1X36003 Version 2.52
1996-1999 Ingersoll-Rand Company
Date of Issue: 18-Oct-1999
Function Code Field
For a normal response, the UCM echoes the function code of the original query in the
function code field of the response. All function codes have their most significant bits set to
zero; therefore, the values are always below 80 hexadecimal. When an exception response
occurs, the UCM sets the most significant bit of the function code to 1. This makes the
function code value in an exception response exactly 80 hexadecimal higher than the value
would be for a normal response.
With the function code's most significant bit set, the application program can recognize an
exception response and can examine the data field for the exception code.
Data Field
For a normal response, the UCM will return information in the data field (depending upon the
query message sent). For an exception response, the UCM returns an exception code in the
data field. This defines the UCM’s condition that caused the exception.
Exception Codes Supported by the CMC Microcontroller
Most Significant Bit
Least Significant Bit
7
6
5
4
3
2
1
0
1
0
0
0
0
0
0
0
