Zynq-7000 AP SoC and 7 Series FPGAs MIS v4.1
137
UG586 November 30, 2016
Chapter 1:
DDR3 and DDR2 SDRAM Memory Interface Solution
•
Control Offset
– This field is used to control when the address and command
IN/OUT_FIFOs are read and transferred to the IOIs. The control offset is in units of the
DDR2 or DDR3 SDRAM clock cycle.
•
Auxiliary Output
– This field is used to control when the auxiliary output signals
(Aux_Output[3:0]) are used. Auxiliary outputs can be configured to activate during read
and write commands. The timing offset and duration are controlled by the attributes
described in
. These outputs are not used by the DDR2 and DDR3
interfaces generated by the MIG tool; they are set to 0.
•
Low Index (Bank)
– The dedicated PHY has internal counters that require this field to
specify which of the eight DDR2 or DDR3 SDRAM banks to use for the data command.
The MIG IP core does not use these internal counters; therefore, this field should be all
zeros.
•
Reserved
– This field must always be set to 2'b00.
•
Data Offset
– This field is used to control when the data IN/OUT_FIFOs are read or
written based on the PHY command. The data offset is in units of the DDR2 or DDR3
SDRAM clock cycle.
•
Seq
– This field contains a sequence number used in combination with the
Sync_In
control signal from the PLL to keep two or more PHY control blocks executing the
commands read from their respective control queues in sync. Commands with a given
seq value must be executed by the command parser within the PHY control block
during the specific phase indicated by the Seq field.
•
CAS Slot
– The slot number being used by the Memory Controller for write/read (CAS)
commands.
•
Event Delay
– The dedicated PHY has internal counters that require this field to specify
the delay values loaded into these counters. The event delay is in units of DDR2 or
DDR3 SDRAM clock cycles. The MIG IP core does not use these internal counters;
therefore, this field should be all zeros.
•
Activate Precharge
– The dedicated PHY has internal counters that require this field to
specify the type of DDR2 or DDR3 command related to the event delay counter. Valid
values are:
°
00: No action
°
01: Activate
°
10: Precharge
°
11: Precharge/Activate
The MIG IP core does not use these internal counters; therefore, this field should be all
zeros.