33
ECP5 and ECP5-5G Hi
g
h-Speed I/O Interface
• The DQSBUFM is used to generate the Read and Write pointers that is used to transfer data from the DQS to
ECLK inside the IDDRX2DQA module
• Read 1, 0 and Readclksel_2, 1, 0 signals of DQSBUFM are used by the user logic to obtain the optimal READ
pulse position and driven by the user logic to generate a clean DQS output signal based on the trained READ
pulse with respect to preamble and postamble
• The dynamic delay control ports are available on the DQSBUFM module when user selects the “enable dynamic
margin control” option
• DYNDELAY[7:0] of DQSBUFM is used to perform write leveling. If write leveling is not used, it is connected to “0”.
• Port QWL of IDDRX2DQA is used for DDR3/DDR3L and LPDDR3 to support write leveling. It is used to deliver
the write leveling monitor signals from the memory device to the FPGA user logic.
• MEM_SYNC soft IP must always be included in the interface. It is required to avoid issues on DDR memory bus
and update code in operation without interrupting interface operation. When a DDR memory interface IP is gen-
erated from Clarity Designer, the MEM_SYNC soft IP block is also generated and included.
• The Pause_sync output of the MEM_SYNC soft IP is used to request DQSBUFM pause for the DDRDLL update
and goes to an output port of the Clarity Designer module. The input port Pause_data goes to DQSBUFM. It is
required by user logic, to OR the Pause_sync output of the MEM_SYNC module with the user pause to drive the
Pause_data input of the DQSBUFM. This OR would need to be implemented outside of the Clarity Designer
module in user’s design.
• CLKDIVF set to divide by 2 function is used to generate the SCLK from the ECLK
• When DDR data bus is required to cross two sides, an ECLKBRIDGECS should be enabled in Clarity Designer.
When using ECLKBRIDGECS, there will be two DDRDLLs in the design one for each side. Also the DQSBUFMs
used on the second side should be connected to its DDRDLL. Clarity Designer will automatically generate all the
required DDRDLLs and DQSBUFMs
Write Implementation (DQ, DQS and DM)
Figure 32 shows the DDR2, DDR3/DDR3L, LPDDR2 and LPDDR3 memory interface write side implementation to
generate DQ, DQS and DM outputs.