AR# 40653: 12.2 EDK, MPMC - Reduced drive output enable C_MEM_REDUCED_DRV not set correctly
AR# 40653
12.2 EDK, MPMC - Reduced drive output enable C_MEM_REDUCED_DRV not set correctly
Description
When I set the MPMC parameter C_MEM_REDUCED_DRV to "1" in Virtex-6 FPGA, MPMC sets DDR3 mode register MR1[5,1] to "00". In Spartan-6 FPGA, the opposite setting is set. Which is correct?
According to the MPMC data sheet, the description of C_MEM_REDUCED_DRV for DDR3 is as follows:
0 = RZQ/6 1 = RZQ/7 2 = Reserved 3 = Reserved
Solution
In Virtex-6 FPGA, setting C_MEM_REDUCED_DRV = 1 will correctly produce a reduced drive setting of RZQ/6. However, the data sheet and MPMC GUI labels are incorrect. It will be fixed to:
0 = RZQ/7 1 = RZQ/6 2 = Reserved 3 = Reserved
In Spartan-6 FPGA MPMC, the behavior of C_MEM_REDUCED_DRV is inverted from its normal meaning. To work around, invert the parameter until this issue is fixed. These issues are scheduled to be fixed in EDK 13.2.