Programmable Logic - 2025.2 English - UG1273

Versal Adaptive SoC Design Guide (UG1273)

Document ID
UG1273
Release Date
2025-12-03
Version
2025.2 English

The Versal adaptive SoC programmable logic (PL) comprises configurable logic blocks (CLBs), internal memory, and DSP engines. Every CLB contains 64 flip-flops and 32 look-up tables (LUTs). Half of the CLB LUTs can be configured as:

  • 64-bit RAM, as a 32-bit shift register (SRL32), or
  • Two 16-bit shift registers (SRL16)

In addition to the LUTs and flip-flops, the CLB contains the following:

  • Carry lookahead logic for implementing arithmetic functions or wide logic functions
  • Dedicated, internal connections to create fast LUT cascades without external routing

This enables a flexible carry logic structure that allows a carry chain to start at any bit in the chain. In addition to the distributed RAM (64-bit each) capability in the CLB, there are dedicated blocks for optimally building memory arrays in the design:

Accelerator RAM (4 MB)
Available in some Versal devices only
Block RAM (36 Kb each)
Where each port can be configured as 4Kx9, 2Kx18, 1Kx36, or 512x72 in simple dual-port mode
UltraRAM (288 Kb each)
Where each port can be configured as 32Kx9, 16Kx18, 8Kx36, or 4Kx72

Versal devices also include many low-power DSP Engines, combining high speed with small size while retaining system design flexibility. The DSP engines can be configured in various modes to better match the application needs:

  • 27×24-bit twos complement multiplier and a 58-bit accumulator
  • Three element vector/INT8 dot product
  • Complex 18bx18b multiplier
  • Single precision floating point

For more information on PL resources, see the following documents:

  • Versal Adaptive SoC DSP Engine Architecture Manual (AM004)
  • Versal Adaptive SoC Configurable Logic Block Architecture Manual (AM005)
  • Versal Adaptive SoC Memory Resources Architecture Manual (AM007)