Variable Precision DSP Blocks User Guide: Agilex™ 5 FPGAs and SoCs

ID 813968
Date 9/20/2024
Public
Document Table of Contents

5.6.7. 27 × 27 Mode Signals

Figure 72. 27 × 27 Mode Signals


Table 85.  Data Input and Output Signals
Signal Name Type Width Description
ax[26:0] Input 27 Input data bus to the multiplier.

This signal is not available when internal coefficient feature is enabled.

ay[26:0] Input 27 Input data bus to the multiplier.

When pre-adder is enabled, these signals are served as input to the pre-adder.

az[25:0] Input 26

These signal are input to the pre-adder.

These signals are only available when pre-adder is enabled.

resulta[63:0] Output 64 Output data bus from the multiplier.
Table 86.  Clock, Enable, and Clear Signals
Signal Name Type Width Description
clk[0] Input 1 Input clock for all registers.
ena[2:0] Input 3 Clock enable signals for all registers.

Clock enable signals have higher priority compared to the SCLR signals.

These signals are active-High.

clr[1:0] Input 2 These signals can be asynchronous or synchronous clear input signals for all registers. You may select the type of clear input signal using Type of clear signal parameter.

These signals are active-High.

By default, this signal is low.

For more information about clock enable restrictions for input registers, refer to the related information.

Table 87.  Dynamic Control SignalsFor a summary of supported dynamic control features for each operational mode, refer to the related information.
Signal Name Type Width Description
disable_chainout Input 1 Dynamic input signal to enable dynamic chainout feature. You can change the value of this signal during run-time.

You must connect the chainout output bus to the next DSP block in order to use this signal.

  • 0: Send the chainout output to the next DSP block. Default value.
  • 1: Do not send the chainout output to the next DSP block. The chainout output is all zero.
accumulate Input 1 Input signal to enable or disable the accumulator feature. You can change the value of this signal during run-time.
  • 0: Generate the current result without accumulating the previous result. Default value.
  • 1: Add the current result to the previous result.
loadconst Input 1 Input signal to enable or disable the load constant feature. You can change the value of this signal during run-time.
  • 0: Disable the load constant feature. Default value.
  • 1: Add a preload constant to the result to perform a biased rounding.
negate Input 1 Dynamic input signal to control the operation of the chainout adder module. You can change the value of this signal during run-time.
  • 0: Add the sum of the top and bottom multipliers with the chainin data input bus and accumulate loopback data. Default value.
  • 1: Subtract the sum of the top and bottom multipliers from the chainin data input bus and accumulate loopback data.
Table 88.  Internal Coefficient PortsFor a summary of supported features for each operational mode, refer to the related information.
Signal Name Type Width Description
coefsela[2:0] Input 3 Input selection signals for 8 coefficient values defined by user for the top multiplier. The coefficient values are stored in the internal memory and specified by parameters coef_a_0 to coef_a_7.
  • coefsela[2:0] = 000 refers to coef_a_0
  • coefsela[2:0] = 001 refers to coef_a_1
  • coelsela[2:0] = 010 refers to coef_a_2 and so forth.

These signals are only available when the internal coefficient feature is enabled.

Table 89.  Input Cascade Signals
Signal Name Type Width Description
scanin[26:0] Input 27 Input data bus for input cascade module.

Connect these signals to the scanout signals from the preceding DSP core.

scanout[26:0] Output 27 Output data bus of the input cascade module.

Connect these signals to the scanin signals of the next DSP core.

Table 90.  Output Cascade Signals
Signal Name Type Width Description
chainin[63:0] Input 64 Input data bus for output cascade module.

Connect these signals to the chainout signals from the preceding DSP core.

chainout[63:0] Output 64 Output data bus of the output cascade module.

Connect these signals to the chainin signals of the next DSP core.