AHB-Lite to TL-UL Bridge

What it is

ahb_to_tl_ul is a single-clock, single-outstanding protocol bridge that turns an AMBA 3 AHB-Lite subordinate port into a TileLink Uncached-Lightweight (TL-UL) manager port, translating each accepted AHB NONSEQ transfer into one TL-UL GET/PUT round trip.

Key Features

• Single-outstanding AHB-Lite NONSEQ → TL-UL GET/PUT_FULL/PUT_PARTIAL translation via a four-state FSM (IDLE→DATA→WAIT_D→RESPOND); the write byte-mask from HSIZE/HADDR selects PUT_FULL vs PUT_PARTIAL
• Single clock domain, no CDC: the AHB capture registers, FSM, and safety monitor all run off one clk/rst_n pair — verified directly against the RTL port list
• Configurable TIMEOUT_CYCLES watchdog (default 256) catches a stalled TL-UL fabric and returns HRESP=ERROR (err_code 4) instead of hanging the AHB bus indefinitely
• Read-path SECDED ECC on the captured TL-D response word — single-bit errors corrected transparently, double-bit errors flagged err_code 2; write data (HWDATA) passes through combinationally, unbuffered
• Even parity on the latched AHB address (saved_haddr_q), checked outside IDLE — err_code 1 on an address-register upset
• Complementary-redundant diverse-DMR FSM lockstep: an independent next-state cone recomputes the state from ~state_cmpl_q and flags any divergence from the live FSM — err_code 9
• Catalog FMEDA (pre-sign-off engineering numbers): SPFM 91.80%, LFM 89.35%, PMHF 1.30×10⁻⁹/h — PASS against the ASIL-B target with margin on every metric

Standards & Compliance

AMBA 3 AHB-Lite; TileLink Uncached-Lightweight (TL-UL); ISO 26262 ASIL-B SEooC (SPFM 91.80%, LFM 89.35%, PMHF 1.30×10⁻⁹/h)

Functional Safety

ASIL-B (SEooC) · SPFM 91.80% · LFM 89.35% · PASS

ISO 26262:2018 · FMEDA available · Safety Manual included

Register Map

See datasheet for full register reference.

Getting Started

// Minimal instantiation
ahb_to_tl_ul #(
  .ADDR_W(6)
) u_ahb_to_tl_ul (
  .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.