In some cases Connect Tech may have produced FreeForm/104 products using Spartan-3E silicon Stepping Number 0.
This might impact several timing parameters including DCM performance
Differences between steppings
From Xilinx DS312 Table 71:
- Production from 2005 to 2007
- Speed grade and operating conditions = 4C only
- DCM maximum input frequency = 90 MHz
- DCM DFS output frequency range = 5 – 90 MHz and 220 – 307 MHz
- JTAG ID = 0x01C 22 093 or 0x11C 22 093
- Production from 2006 to now
- Speed grade and operating conditions = -4C, -4I, -5C
- DCM maximum input frequency = 240 MHz
- DCM DFS output frequency range = 5 – 311 MHz
- JTAG ID = 0x21C 22 093
Only commercial temperature grade boards (FBG001, FBG002, FBG003, FBG004, FBG008) are affected.
How to determine if a board uses a device with Stepping 0
Designing with Stepping 0
It is not possible for the Xilinx ISE tools ( after ISE 8.x) to target the stepping code; so the designer will have to be aware of the limitations.
Originally from kdb339: FreeForm/104 Spartan 3E Steppings