ALTIOBUF IP Core User Guide

ID 683471
Date 1/13/2020

Assignments Necessary For Dynamic Delay Chain Usage

If you utilize the dynamic delay chain for the I/O buffer IP core, a MEMORY_INTERFACE_DATA_PIN_GROUP assignment to the I/O buffer block is necessary to enable it to go through fitting.

This is because the IP core utilizes the IO_CONFIG and DELAY_CHAIN blocks that are associated with the use of DDR interfaces. Therefore, the Intel® Quartus® Prime Fitter requires the assignment to determine the placement of the blocks with the respective IO_xBUF block.

The format of the MEMORY_INTERFACE_DATA_PIN assignments generally appears as the following:

MEMORY_INTERFACE_DATA_PIN_GROUP {4|9|18|36} -from iobuf[0] -to iobuf[0]
MEMORY_INTERFACE_DATA_PIN_GROUP {4|9|18|36} -from iobuf[0] -to iobuf[1]
MEMORY_INTERFACE_DATA_PIN_GROUP {4|9|18|36} -from iobuf[0] -to iobuf[2]
MEMORY_INTERFACE_DATA_PIN_GROUP {4|9|18|36} -from iobuf[0] -to iobuf[n]

iobuf is the name of the buffer, either a stratixiii_io_obuf (for the output buffer) or stratixiii_io_ibuf (for the input buffer). For the bidirectional buffer, either one is acceptable.

Figure 9. Output BufferThis figure shows an example of an output buffer.

To allow this particular design to be fit, add the following line in the Intel® Quartus® Prime Setting File (.qsf):

set_instance_assignment -name MEMORY_INTERFACE_DATA_PIN_GROUP 4 -from "u2|test_output_iobuffer_iobuf_out_kk21:test_output_iobuffer_iobuf_out_kk21_component|obufa_0" -to "u2|test_output_iobuffer_iobuf_out_kk21:test_output_iobuffer_iobuf_out_kk21_component|obufa_0"

You can also use the Assignment Editor to set the column fields as shown in the following table:

Table 4.  Assigning the MEMORY_INTERFACE_DATA_PIN_GROUP Assignment
Column Setting
From u2|test_output_iobuffer_iobuf_out_kk21:test_output_iobuffer_iobuf_out_kk21_component|obufa_0
To u2|test_output_iobuffer_iobuf_out_kk21:test_output_iobuffer_iobuf_out_kk21_component|obufa_0
Value 4
Enable Yes

Then, set the Value field as shown in the following table:

1–6 4
7–12 9
13–24 18
25–48 36

The design example associated with this user guide has this assignment.

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