How do I set ODT values for the for the Zynq PS7 DDR Controller?
(UG585), states that the ODT values can be changed:
"10.6.6 DRAM Input Impedance (ODT) Calibration
The on-die-termination (ODT) is available in DDR2 and DDR3 devices with the following features:
In DDR3 devices, the ODT value is controlled via Mode register MR1. It can be disabled, or set to one of the following values: 120, 60, or 40.
In DDR2 devices, the ODT value is controlled via the mode register EMR. It can be disabled, or set to one of the following values: 75, 150, or 50.
Both DDR2 and DDR3 devices have a dedicated ODT input pin that is used to enable the ODT during write operations, and disable it otherwise."
Vivado does not allow you to change ODT values from the GUI.
To change the ODT values for DDR3, you must change the MR1 register manually in the ps7_init.tcl and/or ps7_init.c files.
The following register names correspond to the following MR registers:
The values are in hexadecimal.
The bit definition for MR# registers can be found in the DRAM datasheet.