Reading DRAM Configuration Mode Registers

Zynq UltraScale+ Device Technical Reference Manual (UG1085)

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2.4 English

This section describes how to perform mode register reads and writes via software. Mode register reads (MRR) are applicable only to LPDDR2/LPDDR3/LPDDR4, and are used to read configuration and status data from mode registers in the SDRAM. Mode register writes (MRW or MRS) are applicable to all supported DDR protocols, and are used to write configuration data to mode registers in the SDRAM.

For DDR4, the PS DDR also supports Multi-purpose register (MPR) reads and writes.