178 www.xilinx.com 7 Series FPGAs SelectIO Resources User Guide
UG471 (v1.10) May 8, 2018
Chapter 3: Advanced SelectIO Logic Resources
used when the output clock frequency is twice the input clock frequency and thus
output data is half the width of the input data. Table 3-17 shows the 8 x 4 mode
mapping in detail.
Both modes support the FULL, EMPTY, ALMOSTFULL, and ALMOSTEMPTY flags.
OUT_FIFO Primitive
The OUT_FIFO primitive is shown in Figure 3-21.
Table 3-17: OUT_FIFO Input to Output Data Mapping
Mapping Not Used
D0[7:0] → Q0[3:0]
D1[7:0] → Q1[3:0]
D2[7:0] → Q2[3:0]
D3[7:0] → Q3[3:0]
D4[7:0] → Q4[3:0]
D5[7:0] → Q5[3:0]
D6[7:0] → Q6[3:0]
D7[7:0] → Q7[3:0]
D8[7:0] → Q8[3:0]
D9[7:0] → Q9[3:0]