Zynq-7000 AP SoC and 7 Series FPGAs MIS v4.1
437
UG586 November 30, 2016
Chapter 3:
RLDRAM II and RLDRAM 3 Memory Interface Solutions
shows the timing diagram for a typical RLDRAM II configuration 3, burst length
of four with commands being sent to the PHY from a controller. After
cal_done
is asserted,
the controller begins issuing commands. A single write command is issued by asserting the
cs0
and
we0
signals (with
ref0
being held Low) and ensuring that
addr0
and
ba0
are
valid. Because this is a burst length of four configuration, the second command that must
be issued is a No Operation (NOP), that is, all the control signals (
cs1
,
we1
,
ref1
) are held
Low.
Two clock cycles later, the
wr_en0/1
signals are asserted, and the
wr_data0/1
and
wr_dm0/1
signals are valid for the given write command. In this same clock cycle, a single
read command is issued by asserting
cs0
(with
we0
and
ref0
being held Low) and placing
the associated addresses on
addr0
and
ba0
. Two refresh commands are issued by asserting
cs0/1
,
ref0/1
, and
ba0/1
. The refresh commands can be issued in the same clock cycle
as long as the memory banking rules are met.
rld_dq
Input/Output
Data DQ. This is a bidirectional data port, driven by the FPGA for writes and
by the memory for reads.
rld_qk_p
Input
Read Clock QK. This is the read clock returned from the memory edge aligned
with read data on
rld_dq. This clock (in conjunction with QK#) is used by the
PHY to sample the read data on
rld_dq.
rld_qk_n
Input
Read Clock QK#. This is the inverted read clock returned from the memory.
This clock (in conjunction with QK) is used by the PHY to sample the read
data on
rld_dq.
rld_reset_n
Output
RLDRAM 3 reset pin. This is the active-Low reset to the RLDRAM 3 device (not
used for RLDRAM II).
Table 3-12:
Physical Interface Signals
(Cont’d)
Signal
Direction
Description