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Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 850
UG585 (v1.11) September 27, 2016
Appendix B: Register Details
Register (ddrc) DRAM_param_reg4
Register DRAM_param_reg4 Details
reg_ddrc_t_rrd 7:5 rw 0x6 tRRD - Minimum time between activates from
bank A to bank B. (spec: 10ns or less)
DRAM RELATED
reg_ddrc_t_ccd 4:2 rw 0x4 tCCD - Minimum time between two reads or two
writes (from bank a to bank b). DRAM related.
reserved 1:0 ro 0x0 Reserved
Name DRAM_param_reg4
Relative Address 0x00000024
Absolute Address 0xF8006024
Width 28 bits
Access Type mixed
Reset Value 0x0000003C
Description DRAM Parameters 4
Field Name Bits Type Reset Value Description
Field Name Bits Type Reset Value Description
reg_ddrc_mr_rdata_val
id
27 clronr
d
0x0 This bit indicates whether the Mode Register
Read Data present at address 0xA9 is valid or not.
This bit is 0 by default. This bit will be cleared (0),
whenever a Mode Register Read command is
issued. This bit will be set to 1, when the Mode
Register Read Data is written to register 0xA9.
reg_ddrc_mr_type 26 rw 0x0 Indicates whether the Mode register operation is
read or write
0: write
1: read
ddrc_reg_mr_wr_busy 25 ro 0x0 Core must initiate a MR write / read operation
only if this signal is low. This signal goes high in
the clock after the controller accepts the write /
read request. It goes low when (i) MR write
command has been issued to the DRAM (ii) MR
Read data has been returned to Controller. Any
MR write / read command that is received when
'ddrc_reg_mr_wr_busy' is high is not accepted.
0: Indicates that the core can initiate a mode
register write / read operation.
1: Indicates that mode register write / read
operation is in progress.