Files
FPGA-Neural/hardware/v2/logs
micheleandClaude Sonnet 5 6cff2c8a7c feat(v2): M8 PSRAM integration - real V1 backend shared across concurrent slots
neural_multiprocessor.v wraps dataflow_core.v (M7, unmodified) around
the real, unmodified V1 PSRAM backend chain (int8_memory_access ->
memory_interface -> psram_controller), funneling N_SLOTS independent
Memory Backend Interface ports through a new generic N-port arbiter
(slot_mem_arbiter.v) inspired by (not copied from) V1's own
mem_arbiter.v.

Real concurrent-slot simulation immediately surfaced a genuine bug
(ERR-0008): memory_manager/prefetch_engine's byte-level backend
protocol is fire-and-forget (a single-cycle mem_req pulse with no
accept handshake) - correct for M4's direct 1:1 connection, but a
naive arbiter silently drops a pulse arriving while the shared bus is
owned by another slot, hanging that slot forever. Fixed with a
per-port pending-request latch, the same "queue, don't drop" idiom
already used by memory_manager's own pf_pending register (ERR-0006).

Verified (Verilator): 4/4 PASS with 2 slots genuinely contending for
one real PSRAM port (444 cycles). No regression on M4's own
testbench. Real synthesis + nextpnr-ecp5 P&R (no harness needed - real
PSRAM pins keep the top-level at 157 pins): 0 problems, Fmax 142.45
MHz, PASS at 80MHz.

Arbitration policy is fixed lowest-index priority, not fairness-
balanced (DEC-0010) - consistent with every other "simplest correct
policy first" scheduling choice in this roadmap, revisited only if
M9's real measurement shows starvation matters.

Logged: simulation/synthesis/timing/benchmark/decisions (DEC-0010)/
experiments (EXP-0009)/errors (ERR-0008)/development.log, ROADMAP.md
updated.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v
2026-09-05 15:13:11 +02:00
..

Formato dei log V2

Regola non negoziabile (docs/v2-description.md §25-29): ogni attività significativa (modifica, simulazione, sintesi, benchmark, decisione, errore) deve essere registrata. Nessun log viene mai sovrascritto o troncato — solo append. Nessun ID esperimento (EXP-XXXX) o decisione (DEC-XXXX) viene mai riutilizzato, anche se il risultato è un FAIL.

File

  • development.log — log principale di sviluppo, un'entry per ogni sessione di lavoro/milestone (creazione file, refactor, avanzamento roadmap).
  • architecture.log — decisioni e note di architettura a grana fine (non scelte finali — quelle vanno in decisions.log — ma esplorazioni, alternative considerate, vincoli scoperti).
  • simulation.log — ogni run di simulazione (Icarus/Verilator): test, vettori, cicli, PASS/FAIL, confronto bit-exact con V1, stall/memory-wait.
  • synthesis.log — ogni run Yosys: LUT/FF/DSP/BRAM, warning, problemi CHECK.
  • timing.log — ogni run nextpnr-ecp5: Fmax, percorso critico, WNS/TNS se disponibili. Fmax "ufficiale" di una configurazione = solo da qui, mai da simulazione o stima.
  • benchmark.log — tabelle di confronto per configurazione (Fmax, MAC/cycle, cycles/neuron, utilization, ecc.), sempre con etichetta THEORETICAL/SIMULATED/SYNTHESIZED/POST-P&R.
  • decisions.log — decisioni architetturali importanti, formato DEC-XXXX (vedi docs/v2-description.md §27).
  • experiments.log — registro principale, un EXP-XXXX per ogni esperimento end-to-end (config → sim/synth/timing → risultato), rimanda a reports/experiments/EXP-XXXX/.
  • errors.log — errori/bug/regressioni incontrati durante lo sviluppo V2 stesso (non i bug V1, già chiusi in hardware/v1/docs/validation/bugs.md).

Campi minimi per entry (§26)

timestamp, experiment_id (se applicabile), git_commit, session/agent,
module, configuration, action, reason, command, result, errors, decision,
next_action

Per synthesis/timing aggiungere: LUT, FF, DSP, BRAM, Fmax, critical path, WNS/TNS. Per simulazione: test, vectors, cycles, PASS/FAIL, bit-exact result, stall cycles, memory wait, utilization.