Answers Database MAKEBITS 5.0:XC3000A/L,3100A: Input does not appear to be connected internally Record #356 Problem Title: MAKEBITS 5.0:XC3000A/L,3100A: Input does not appear to be connected internally Problem Description: Solution 1: In XC3000A, XC3000L, and XC3100A devices, there is a bitstream generation problem that may cause IOBs configured as inputs to not be connected internally. The problem occurs when a design uses one of the following pins: PART PAD # EDITLCA PIP NAME ---- ----- --------------------- 3020A/L,3120A 63 row.B.long.1.PAD63.I 3030A/L,3130A 79 row.B.long.1.PAD79.I 3042A/L,3142A 95 row.B.long.1.PAD95.I 3064A/L,3164A 119 row.B.long.1.PAD119.I 3090A/L,3190A 143 row.B.long.1.PAD143.I 3195A,3195L 175 row.B.long.1.PAD175.I If one of these pips is used, the corresponding input to the part will not be connected correctly internally. You can check to see if the pip is used by calling up the design in EDITLCA, then typing "find " followed by the pip name shown in the table above. You can check to see if the input is used by typing "find PAD" followed by the PAD number shown in the table above. Alternatively, you could use the UNIX "grep" command to search for the pip name in the .lca file. A patch is available from Xilinx that fixes this problem, and is being shipped as soon as possible (this was written 8/1/94) to all customers. End of Record #356 - Last Modified: 04/01/97 07:42

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