Zynq-7000 AP SoC and 7 Series FPGAs MIS v4.1
583
UG586 November 30, 2016
Chapter 4:
LPDDR2 SDRAM Memory Interface Solution
wr_data
This bus is the data that needs to be written to the external memory. This bus can be
connected to the data output of a buffer in the user design.
wr_data_addr
This bus is an echo of data_buf_addr when the current write request is submitted. The
wr_data_addr
bus can be combined with the
wr_data_offset
signal and applied to
the address input of a buffer in the user design.
wr_data_mask
This bus is the byte enable (data mask) for the data currently being written to the external
memory. The byte to the memory is written when the corresponding
wr_data_mask
signal
is deasserted.
wr_data_en
When asserted, this signal indicates that the core is reading data from the user design for a
write command. This signal can be tied to the chip select of a buffer in the user design.
wr_data_offset
This bus is used to step through the data buffer when the burst length requires more than
a single cycle to complete. This bus, in combination with
rd_data_addr
, can be applied to
the address input of a buffer in the user design.
Read Command Signals
The native interface provides a set of signals used when the Memory Controller is
processing a read command (
). These signals are similar to those for processing
write commands, except that they transfer data from the memory device to a buffer in the
user design.
wr_data_en
Output
This output indicates that the memory
interface is reading data from a data
buffer for a write command.
wr_data_offset[0:0]
Output
This output provides the offset for the
source data buffer for write commands.
Table 4-18:
Native Interface Write Command Signals
(Cont’d)
Signal
Direction
Description