Answers Database
2.1i 4KX* Bitgen - Some 4000x family devices won't configure via JTAG
Record #7318
Product Family: Software
Product Line: FPGA Implementation
Product Part: bitgen
Product Version: 2.1i
Problem Title:
2.1i 4KX* Bitgen - Some 4000x family devices won't configure via JTAG
Problem Description:
The algorithm used to calculate the required bitstream length doesn't always provide enough clocks t
o allow the device to configure via the JTAG port. Configuration via JTAG requires 3 more clocks tha
n configuration via the "normal" serial and parallel configuration modes. We currently round the bit
stream up to a byte boundary. In the old 4000 and 4000e devices this results in adding 3 extra bits
which conveniently is the number needed for JTAG. In some of the newer 4000x devices no extra bits a
re needed to reach a byte boundary. These devices end up with a bitstream that is too short for JTAG
configuration. There are 11 devices that fall into this category. The devices are: 4036ex 4005xl 40
10xl 4020xl 4036xl 4052xl 4020xla 4036xla 4052xla s05xl s10xl
A fix for this problem is included in the 2.1i Service Pack 2 Update.
Solution 1:
A fix for this problem is planned for the 2.1i Service Pack 2 Update.
End of Record #7318 - Last Modified: 09/02/99 14:28 | 
