Answers Database
XNFPREP: Certain IOB primitive configuration statements cause errors
Record #262
Problem Title:
XNFPREP: Certain IOB primitive configuration statements cause errors
Problem Description:
Solution 1:
When using the XC3000 family IOB primitive, it is necessary to add text to it
specifying the configuration of the IOB. If the "IN:" statement is written
so that the "I" tag is listed after the "FF" or "LATCH" tag, XNFPREP may
incorrectly trim the I pin from the IOB configuration. For example, the
following configuration statement will not work correctly, as the "I"
connection will be trimmmed:
IN:FF:I:IQ OUT:OQ TRI:
wrong order -----^--^
However, a functionally identical configuration statement written with the
"I" tag before the "FF" or "LATCH" tag will work correctly, as shown below:
IN:I:FF:IQ OU:OQ TRI:
right order ------^--^
Note that it is not always necessary to use these tags. When it is necessary,
however, be sure that the "I" tag follows the "IN:" statement.
End of Record #262 - Last Modified: 04/01/97 07:27 |
