Files
FPGA-Neural/hardware/v1/rtl/memory_interface.v
micheleandClaude Sonnet 5 dc0b331d3e feat(v2): scaffold hardware/v1 frozen baseline + M1 Neural Processor
Begins the V2 Neural Multiprocessor / Dataflow architecture per
docs/v2-description.md, per explicit user request to freeze V1 and
start V2 development, copying from V1 what's needed.

Scaffold:
- hardware/v1/: byte-exact, read-only copy of the current V1 codebase
  (rtl, testbenches, tools, constraints, a representative subset of
  synthesis results, and reference docs) -- verified identical via
  diff/cmp against the live top-level tree before being made
  filesystem-read-only. The live top-level tree is untouched and
  remains the project's "production" V1 (see hardware/v1/README.md
  and hardware/v2/logs/decisions.log DEC-0001 for why copy-not-move).
- hardware/v2/: mandatory structure (rtl/sim/constraints/synthesis/
  reports/scripts/logs/docs) plus the full logging system required by
  the spec (development/architecture/simulation/synthesis/timing/
  benchmark/decisions/experiments/errors.log).

M1 -- Neural Processor (hardware/v2/rtl/neural_processor.v):
- 8-stage pipelined perceptron unit (P_IN=8): input align, 8
  multipliers, 3-level adder tree, accumulator, bias+activation, INT8
  saturation. Genuine 1-tile/cycle throughput, not just a wider
  combinational datapath.
- 7-state FSM (NP_IDLE..NP_ERROR per docs/v2-description.md §6, with
  4 baseline states merged into NP_WAIT_OPERANDS -- see
  decisions.log DEC-0002); valid/ready/data/last stream interfaces
  per §7.
- Bit-exact vs the frozen hardware/v1/rtl/neuron_parallel.v + mac8.v
  + mac_unit.v: 7/7 tests pass (hardware/v2/sim/tb_neural_processor.v),
  covering regular/mixed-sign/extreme-INT8 vectors, both activations,
  a zero-idle-gap back-to-back-tiles throughput check, and an 8-tile
  job -- verified with Verilator (see below for why).
- Real synthesis + place&route (Yosys + nextpnr-ecp5): 0 CHECK
  problems, Fmax 183.12 MHz at ACC_WIDTH=32 (PASS at 80MHz, ~3x V1's
  isolated PARALLEL=8 Fmax of 61.71 MHz) and 176.21 MHz at ACC_WIDTH=24
  (a user-requested comparison experiment, also bit-exact-verified;
  see experiments.log EXP-0001/EXP-0002 and benchmark.log).

Three real bugs found and resolved during M1 development (full
diagnostic record in errors.log):
- Two independent, reproducible Icarus Verilog v13.0 scheduling
  defects (ERR-0001, ERR-0002) that silently produced wrong simulation
  results for standard sequential Verilog -- confirmed via Verilator
  5.050 giving correct results on the same minimal repros. Verilator
  is now the trusted simulator for hardware/v2/ (decisions.log
  DEC-0004); Icarus's affected protocol-violation check was removed
  from the RTL and deferred architecturally to the Neural Director
  (DEC-0003) rather than chased further.
- One real RTL bug (ERR-0003): last0 wasn't gated like valid0,
  letting a "last tile" tag leak into the pipeline ahead of its
  actual valid tile on back-to-back jobs. Fixed and verified.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v
2026-09-05 14:06:53 +02:00

94 lines
2.4 KiB
Verilog

module memory_interface #(
parameter ADDR_WIDTH = 23,
parameter DATA_WIDTH = 16
)(
input wire clk,
input wire rst,
input wire req,
input wire wr,
input wire [ADDR_WIDTH-1:0] addr,
input wire [DATA_WIDTH-1:0] wdata,
input wire lb_n,
input wire ub_n,
output reg [DATA_WIDTH-1:0] rdata,
output reg ready,
output reg mem_req,
output reg mem_wr,
output reg [ADDR_WIDTH-1:0] mem_addr,
output reg [DATA_WIDTH-1:0] mem_wdata,
output reg mem_lb_n,
output reg mem_ub_n,
input wire [DATA_WIDTH-1:0] mem_rdata,
input wire mem_ready
);
localparam STATE_IDLE = 2'd0;
localparam STATE_WAIT = 2'd1;
reg [1:0] state;
always @(posedge clk) begin
if (rst) begin
state <= STATE_IDLE;
rdata <= {DATA_WIDTH{1'b0}};
ready <= 1'b0;
mem_lb_n <= 1'b1;
mem_ub_n <= 1'b1;
mem_req <= 1'b0;
mem_wr <= 1'b0;
mem_addr <= {ADDR_WIDTH{1'b0}};
mem_wdata <= {DATA_WIDTH{1'b0}};
end else begin
// Default: pulses
ready <= 1'b0;
mem_req <= 1'b0;
case (state)
STATE_IDLE: begin
if (req) begin
// Latch transaction
mem_wr <= wr;
mem_addr <= addr;
mem_wdata <= wdata;
mem_lb_n <= lb_n;
mem_ub_n <= ub_n;
// Issue exactly one-cycle request
mem_req <= 1'b1;
state <= STATE_WAIT;
end
end
STATE_WAIT: begin
// Wait for memory completion
if (mem_ready) begin
if (!mem_wr)
rdata <= mem_rdata;
ready <= 1'b1;
state <= STATE_IDLE;
end
end
default: begin
state <= STATE_IDLE;
end
endcase
end
end
endmodule