Stratix® V Device Handbook: Volume 1: Device Interfaces and Integration

ID 683665
Date 10/18/2023
Public
Document Table of Contents

3.5.1. Input Register Bank

The input register bank consists of data, dynamic control signals, and two sets of delay registers.

All the registers in the DSP blocks are positive-edge triggered and cleared on power up. Each multiplier operand can feed an input register or a multiplier directly, bypassing the input registers.

The following variable precision DSP block signals control the input registers within the variable precision DSP block:

  • CLK[2..0]
  • ENA[2..0]
  • ACLR[0]

In 18 x 18 mode, you can use the delay registers to balance the latency requirements when you use both the input cascade and chainout features.

One feature of the input register bank is to support a tap delay line; therefore, you can drive the top leg of the multiplier input (B) from general routing or from the cascade chain, as shown in the following figures. The Stratix® V variable precision DSP block supports 18-bit and 27-bit input cascading.

Figure 26. Input Register of a Variable Precision DSP Block in 18 x 18 Mode for Stratix V DevicesThe figures show the data registers only. Registers for the control signals are not shown.


Figure 27. Input Register of a Variable Precision DSP Block in 27x 27 Mode for Stratix V DevicesThe figures show the data registers only. Registers for the control signals are not shown.