The idcode.jam file is an ASCII text file that contains Jam language source code for reading the IEEE Std. 1149.1 Joint Test Action Group (JTAG) IDCODE from any JTAG-compliant Altera® device. This file can be used to debug embedded programming issues when using the Jam Player. The file can provide a good starting point to help determine whether the programming issue is hardware or software related.
You can download a compressed version of the file, called idcode.zip, from the Altera web site.
For information on how to use the idcode.jam file, refer to AN 100 (In-System Programmability Guidelines).