AR# 33375: MIG v3.2, Virtex-6 FPGA RLDRAMII - Valid configurations to avoid tRC violations for -18, -25, -25E, and -33 devices
AR# 33375
MIG v3.2, Virtex-6 FPGA RLDRAMII - Valid configurations to avoid tRC violations for -18, -25, -25E, and -33 devices
Description
The MIG v3.2 Virtex-6 RLDRAMII design has tRC violations for specific configurations. These are actual tRC violations that cannot be ignored. This answer record details valid configurations/frequency ranges that do not generate tRC violations.
Solution
-25 Devices (up to 400 MHz)
Frequency = 175-200 MHz Valid Configurations = 1, 2, 3 Frequency = 201-299 MHz Valid Configurations = 2, 3 Frequency = 300-400 MHz Valid Configurations = 3
-33 Devices (up to 300 MHz)
Frequency = 175-200 MHz Valid Configurations = 1, 2, 3 Frequency = 201-299 MHz Valid Configurations = 2, 3
-25E and -18 Devices (Full Frequency Support)
Frequency = 175-266 MHz Valid Configurations = 1, 2, 3 Frequency = 267-400 MHz Valid Configurations = 2, 3 Frequency = 400-533 MHz Valid Configurations = 2, 3
All 576 Mb, -25 Devices
Because of the tRC violations on all of these devices, support is not available in MIG v3.2. To start in a design, select a comparable RLDRAMII device until support is added in MIG v3.3.
All of these issues will be resolved in MIG 3.3 which will be released with ISE Design Suite 11.4.