AI MAC Cluster

What it is

ai_mac_cluster is the multi-tile integrator for the INT8 systolic-GEMM tile (ai_mac v2): a TILES_M × TILES_N grid of SIZE × SIZE output-stationary PE tiles — default 2×2 of SIZE-4 = effective 8×8, parameterizable to e.g.

Key Features

• TILES_M×TILES_N grid of ai_mac v2 (STREAM_EN=1) SIZE×SIZE tiles — default 2×2 of SIZE-4 = effective 8×8, parameterizable to 4×4 = effective 16×16
• Output-stationary dataflow: activations broadcast along tile-rows, weights broadcast along tile-columns; M/N tiling only — K is fixed at each tile’s SIZE, no cross-tile K-reduction
• Host/DMA-fed, not bus-mapped: dedicated a_row_we/w_row_we row-write load ports and start/busy/done control, with combinational c_rd_row/col/data readback of the assembled C
• Deterministic single-clock-domain execution — no internal CDC — with fixed run latency (2·SIZE distribute beats + per-tile GEMM + SIZE collect rows) for bit-exact regression and FTTI budgeting
• Signed-INT32 accumulation per tile and at the cluster assembler, with ample headroom at the default SIZE=4 geometry (|sum| ≤ 65536 vs 2^31)
• Independent cluster-level ABFT column checksum over the assembled C (err_code 2) plus a complementary-DMR shadow on the cluster control FSM (err_code 9) — beyond each tile’s own ABFT/SECDED/DMR overlay
• One per-cluster fccu fault hub (self-sequenced APB config, err_code 1) aggregates every tile and cluster fault into a single safety_monitor err_valid/err_code[3:0] plus a critical fault_out pin; per-tile fi_* fault-injection port proves diagnostic coverage

Standards & Compliance

ISO 26262 ASIL-B SEooC (SPFM 95.66%, LFM 90.33%, PMHF 7.85×10⁻⁹/h, engineering FMEDA); INT8 systolic-GEMM accelerator (AXI4-Stream tile interconnect, ai_mac v2 tile)

Functional Safety

ASIL-B target (SEooC) · SPFM 95.66% · LFM 90.33% · Informational — not gated

Informational FMEDA — this IP is reported but NOT gated. The SPFM/LFM figures above are engineering estimates from a model that is not held to the ASIL metric gates (QM, safety-by-composition, a vendor-core overlay, or a pre-sign-off Technology Preview, depending on the IP). They are not a certification claim and must not be relied on as one. See the safety manual for this IP’s exact status, assumptions of use, and any open items.

ISO 26262:2018 · FMEDA available · Safety Manual included

Register Map

See datasheet for full register reference.

Getting Started

// Minimal instantiation
ai_mac_cluster #(
 .ADDR_W(6)
) u_ai_mac_cluster (
 .clk (clk),
 .rst_n (rst_n),
 // APB4
 .p_paddr (paddr),
 .p_psel (psel),
 .p_penable (penable),
 .p_pwrite (pwrite),
 .p_pwdata (pwdata),
 .p_prdata (prdata),
 .p_pready (pready),
 // Safety
 .err_clear (1'b0),
 .err_valid (err_valid),
 .err_code (err_code)
);

Configure via the CTRL register after reset to enable the IP and set operating parameters. Monitor err_valid / err_code for any safety faults reported by the built-in safety monitor.