RM0082
DDR memory controller (MPMC)
Doc ID 018672 Rev 1
199/844
wr_dqs_shift [6:0]
Sets the delay for the ddr_close signal to ensure correct data capture in
the I/O logic.
Each increment of this parameter adds a delay of 1/128 of the system
clock. The same delay will be added to the clk_dqs_out signal for each
slice.
(10)
wr_dqs_shift_bypass [9:0]
Sets the delay for the ddr_close signal when the DLL is being
bypassed. This is used to ensure correct data capture in the I/O logic
The value programmed into this parameter sets the actual number of
delay elements in the ddr_close line. If the total delay time programmed
exceeds the number of delay elements in the delay chain, the delay will
be set internally to the maximum number of delay elements available.
(11)
write_modereg [0]
Supplies the EMRS data for each chip select to allow individual chips to
set masked refreshing. When this parameter is set to 1'b1, the mode
parameter(s) [EMRS register] within the DRAM devices will be written.
Each subsequent write_modereg setting will write the EMRS register of
the next chip select. This parameter will always read back as 1'b0.
The mode registers are automatically written at initialization of the
Memory Controller. There is no need to initiate a mode register WRITE
after setting the start parameter in the Memory Controller unless some
value in these registers needs to be changed after initialization.
(12)
writeinterp [0]
Defines whether the Memory Controller can interrupt a WRITE burst
with a READ command. Some memory devices do not allow this
functionality.
1'b0 - The device does not support READ commands interrupting
WRITE commands.
1'b1 - The device does support READ commands interrupting WRITE
commands.
wrlat [2:0]
Defines the WRITE latency since the WRITE command is issued until
the time the WRITE data is presented to the DRAM devices, in cycles.
wrr_param_value_err [3:0]
Shows the weighted round-robin arbitration errors/warnings. This
parameter is read-only.
Bit 0 - The port ordering parameters do not all contain unique values.
Bit 1 - Any of the relative priority parameters have been programmed
with a zero value.
Bit 2 - The relative priority values for any of the ports paired through the
weighted_round_robin_weight_sharing parameter are not identical.
Bit 3 - The port ordering parameter values for paired ports is not
sequential.
1.
For this parameter and the following ones involving pre-charge concepts, please refer to Bank Splitting.
This parameter may not be modified after the start parameter has been asserted.
2.
SPEAR™ Memory Controller does not support the MOBILE feature in DDR2 mode. Therefore, setting this
bit in conjunction with the MOBILE mode enable bit (en_lowpower_mode) will cause an interrupt.
3.
These parameters must be static during normal operation.
4.
These parameters must be static during normal operation. While these parameters default to 0x0, the
minimum valid value is 0x1. The user should program these parameters to a non-zero value during
initialization
5.
This parameter must be static during normal operation.
Table 153.
Memory controller parameters (continued)
Parameter
Description