User-requested hardware notification so the ESP32 can be
interrupt-driven instead of polling STATUS in a loop.
spi_host_bridge_v3.v: new job_out_done input (wired from
neural_director_packed.v, already available at the top level) and new
data_ready_n output. A sticky irq_pending register sets on job_out_done
(latched, survives the pulse itself deasserting) and clears when the
host completes a real STATUS (0x20) or REG_READ(0x02) transaction -
reusing cs_rose, the same real transaction-complete event the module
already relies on elsewhere, not a new mechanism. dir_error is ORed in
live/combinational, not latched. SET has priority over CLEAR on the
rare cycle both coincide.
Real pin: D14, bank 15 (already 3.3V, alongside the SPI bus and
sys_rst) - tentative, not yet a final board decision. Deliberately
added after EXP-0084's own P&R iterations settled, so it didn't
complicate that already-tight I/O/VCCO budget mid-fix. Its own real
P&R verification is deferred to the next real P&R run (already needed
to close EXP-0084's clock-period timing gap), not run separately
against a config already known to fail timing for unrelated reasons.
Real verification: tb_spi_host_bridge_v3.v extended with 10 new checks
(idle state, sticky set, mid-transaction hold, real-acknowledge clear,
unrelated-register non-acknowledge, dir_error live assert/clear).
49/49 PASS.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
Real 32-bit DDR3 widening (2x MT41J128M16JT-125:K chips ganged in
parallel, user's own MIG wizard session). Full RTL adaptation across
the shared ctrl bus (16-bit word -> 32-bit word, BURST_LEN=8 unchanged,
burst payload 128->256 bits):
- mig_native_adapter.v: app_wdf_data/app_rd_data 64->128 bits (real,
confirmed against the regenerated MIG wrapper), beat count unchanged.
- act_tile_fetch.v: real logic change - burst now holds 4 tiles instead
of 2 (sel_lat extended to 2 registered bits, 4-way case mux instead
of 2-way ternary, same request-time-registered-select discipline as
EXP-0081). Not a further bytes/MAC reduction, just what's needed to
keep 100% packing utilization at the larger burst.
- host_mem_bridge.v: real addressing redesign - host-facing 16-bit-word
contract kept unchanged (ESP32 firmware unaffected), internally
translated onto the new 32-bit-native ctrl bus.
- sdram_arbiter_n.v, layer_prefetch_ctrl.v, packed_slot.v,
ddr_prefetch_mgr.v, n2_system_ddr3_top.v: mechanical width bump plus
doubled ddr3_dq/dqs/dm pins and the real differential sys_clk/clk_ref
top-level ports the regenerated MIG now requires.
New burst_mem_model32.v: explicitly synthetic 32-bit test-only burst
memory (the real 16-bit SDR model is genuinely fixed-width, shared by
20+ other tests, correctly not touched). Found and fixed a real
address-aliasing bug in it during bring-up (MEM_ADDR_BITS=16 silently
wrapped a real 0x10000 test address to 0).
Real verification: all isolated testbenches re-verified (10/10, 33/33,
32/32, 7/7, 9/9 PASS), plus real xsim against the real 2-chip DDR3
model (tb_mig_native_adapter.v 12/12 PASS, tb_n2_system_ddr3.v 8/8
PASS, both chips visibly returning different real data).
Real P&R: 5 real bugs found and fixed across iterations (stale
single-ended MIG clock ports, a real VCCO conflict between the flash
SPI bus and the differential reference clock in bank 14 - fixed by
moving flash to bank 16, a stale imported XDC - same bug class as
EXP-0078 but for constraints this time, missing IOSTANDARDs, and two
previously-silently-broken XDC property bugs). Route completes 100%,
but real timing does NOT close: WNS -0.618ns, 213 failing endpoints.
Honest root cause: the violation is inside neural_processor_packed.v's
own packed-MAC accumulation tree, unchanged since EXP-0059 - it has
real margin at the old 155.039MHz ui_clk but not at the new 172.414MHz
the paired clock-period change produced. This is NOT caused by the
32-bit width change itself. Width alone, even at the old clock, already
delivers the full intended 2x bandwidth gain (1.24 -> ~2.48 GB/s) -
width and clock rate are separable levers. Current trustworthy timing
signoff remains EXP-0083 (16-bit, +0.073ns) until the clock period is
reverted toward 3225ps (keeping Data Width=32) in one more real,
user-gated MIG wizard session.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
New ddr_prefetch_mgr.v wraps act_tile_fetch.v with a depth-2 ping-pong
buffer, issuing the next tile's DDR3 fetch as soon as the fetch engine
is free instead of waiting for packed_slot.v to finish consuming the
current tile. Wired into packed_slot.v's tile loop (job-level start
instead of per-tile req), simplifying the S_TILEWAIT join in the process
(ddrpf_tile_valid is level-held, no separate act_seen latch needed).
Verification: new tb_ddr_prefetch_mgr.v (25/25 PASS after fixing a real
testbench polling race found via iteration-tagged tracing, not an RTL
bug), tb_packed_slot.v re-run unmodified (9/9 PASS, bit-identical
results), tb_n2_system_ddr3.v re-run via real xsim against real
ddr3_model.sv (8/8 PASS). Real P&R: WNS +0.073ns (up from EXP-0082's
+0.068ns), LUTs 5644, DSP48E1 16 unchanged, 0 failing endpoints.
Honest result: real A/B on the actual DDR3 backend (same testbench,
before/after) shows a real but modest 2.86% reduction in total
simulated time - smaller than the original hypothesis suggested, because
neural_processor_packed.v already accepts one operand per cycle, so the
per-tile dead time being removed was already small relative to real DDR3
fetch latency. Docs updated to report this honestly rather than oversell
it; the larger multi-slot DDRManager is deferred pending re-measurement
against the (still pending, user-gated) 32-bit channel widening.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
- PHYSICAL_REALIZATION.md: replace stale "1 tile = 1 burst" layout
description with the real EXP-0081/0082 "2 tiles = 1 burst" convention;
add EXP-0082 signoff row and history table.
- ARCHITECTURE_ANALYSIS.md: mark §5.1 (denser activation packing) DONE with
real re-measured numbers (bandwidth ceiling fraction 25%->50%, WNS
+0.030->+0.068ns); add §5.4, the real device-data-backed comparison of
32-bit single-channel widening vs a second independent DDR3 channel
(decided: 32-bit widening, per real DQS/bank pin-conflict analysis);
update scaling-path recommendation to reflect the user's final directive
(widen channel -> build DDRManager -> N=2/4/8/16 tests, N=8 target, N=16
documentary).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
Closes the last major disclosed functional gap: packed_slot.v's
activation data was read through a combinational stand-in since
EXP-0062. New act_tile_fetch.v reads activation tiles directly from
DDR3 (no on-chip buffering needed, unlike weights -- activation data
has no reuse), sharing each slot's existing ctrl port with its own
weight-prefetch engine. Real memory layout: one full BURST_LEN=8-word
burst per tile, deliberately avoiding any runtime-indexed part-select
given this project's thin P&R timing margin (EXP-0078).
Verified at three levels: act_tile_fetch.v alone (6/6), packed_slot.v
with real preloaded activation data (9/9), and the full N=2 system
against real DDR3 via xsim (8/8, 0 errors) -- the first time this
project's compute path has been verified end-to-end with real DDR3
for both weights and activations.
Retired hardware/v3/rtl/n2_system_top.v and its testbench (pre-DDR3
SDR-placeholder era, fully superseded by n2_system_ddr3_top.v).
Also: docs/PHYSICAL_REALIZATION.md (real pinout/parts/timing/protocol
reference for the physical board) and CLAUDE.md (persistent project
instructions for future Claude Code sessions).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
micheleandClaude Sonnet 5