SCPS304 September 2024 TPLD1201-Q1
ADVANCE INFORMATION
This macro-cell can serve as either a 3-bit LUT or as a pipe delay.
When used to implement LUT functions, the 3-bit LUT takes in three input signals from the connection mux and produces a single output, which goes back into the connection mux. These LUTs can be configured to any 3-input user defined function, including the following standard digital logic functions: AND, NAND, OR, NOR, XOR, XNOR, INV.
Table 7-11 provides the truth table for a 3-bit LUT.
IN2 | IN1 | IN0 | OUT |
---|---|---|---|
0 | 0 | 0 | User defined |
0 | 0 | 1 | |
0 | 1 | 0 | |
0 | 1 | 1 | |
1 | 0 | 0 | |
1 | 0 | 1 | |
1 | 1 | 0 | |
1 | 1 | 1 |
Each 3-bit LUT has 8 bits in the OTP to define their output function.
When used to implement a pipe delay, the three input signals from the connection mux go to the delay input (IN), clock (CLK), and reset (nRST) inputs for the flip-flop/latch, with two outputs going back to the connection mux. With this macro-cell, users can select the number of delay stages per output (from 1 to 8) and the output polarity for OUT1.
The pipe delay is an 8-stage delay composed of 8 DFFs. The DFF cells are tied in series where the output of each delay cell goes to the next DFF cell. There are delay output points for each set of the OUT0 and OUT1 outputs to a mux that is used to control the selection of the amount of delay for each pipe delay output.
For normal pipe delay functionality, the nRST input should be high. If nRST input is low, the pipe delay macro-cell is in a reset state and all outputs are low.
Figure 7-7 shows an example of the pipe delay macro-cell with 2 stages of delay selected.