AIE-ML Boot Sequence

Versal ACAP AIE-ML Architecture Manual (AM020)

Document ID
AM020
Release Date
2022-09-28
Revision
1.0 English
This section describes the steps involved in the boot process for the AIE-ML array.
  • The column clock enable value is disabled by default.
  • Memory zeroization hardware logic is added that applies to each of the tile program memory, tile data memory and memory tile data memory. For each of the memories there is a 1-bit memory-mapped AXI4 register that is set to 1 when zeroization starts. When the process is completed, the internal hardware will set this bit to 0.
  1. Power-on and power-on-reset (POR) deassertion: Power is turned on for all modules related to the AIE-ML array, including the PLL. After power-on, the PLL runs at a default speed. The platform management controller (PMC) and NoC need to be up and running before the AIE-ML boot sequence is initiated. After the array power is turned on, the PMC can deassert a POR signal in the AIE-ML array.
  2. AIE-ML array configuration using NPI: After power-on, the PMC uses the NPI interface to program the different global registers in the AIE-ML array (for example, the PLL configuration registers). The AIE-ML configuration image that is required over the NPI for AIE-ML array initialization comes from a flash device.
  3. Enable PLL: Once the PLL registers are configured (after POR), the PLL-enable bit can be enabled to turn on the PLL. The PLL then settles on the programmed frequency and asserts the LOCK signal. The source of the PLL input (ref_clk) is from hsm_ref_clk and is generated in the control interfaces and processing system (CIPS).
    • The generation and distribution of the clock is described in the PMC and PS Clocks chapter of the Versal ACAP Technical Reference Manual (AM011).
  4. Column clock and column reset assertion/de-assertion: Once the PLL is locked, all column clocks are enabled by writing a 1 to a memory-mapped AXI4 register bit. All column resets are then asserted writing a 1 to a memory-mapped AXI4 register bit. After waiting for a number of cycles, all column resets are de-asserted by writing a 0 to the same register bit.
  5. The array is partitioned into one or more independent partitions, with an integer number of AI Engine columns per partition. Isolation is enabled by default in all tiles, therefore must be disabled on the internal edges of each partition.
  6. AIE-ML array programming: The AIE-ML array interface needs to be configured over the memory-mapped AXI4 from the NoC interface. This includes all program memories, AXI4 stream switches, DMAs, event, and trace configuration registers.