GF-IP — IP Block Library

Commands

• add <block> — Copy IP block into current project
• list — Show all available IP blocks
• info <block> — Show block details, ports, parameters

Available Blocks

Block	Description	Verified
fifo_sync	Synchronous FIFO (parameterized width/depth)	lint + sim + formal
fifo_async	Async FIFO with Gray code pointers (CDC)	lint + sim + formal
cdc_2ff	2-flip-flop synchronizer	lint + sim + formal
cdc_handshake	Multi-bit handshake synchronizer	lint + sim + formal
uart	UART TX+RX with configurable baud	lint + sim + formal
spi_master	SPI master (all 4 CPOL/CPHA modes)	lint + sim + formal
axi4lite_slave	AXI4-Lite register slave	lint + sim + formal
debouncer	Button debouncer with edge detection	lint + sim + formal

Block Structure

Each block lives in ${CLAUDE_PLUGIN_ROOT}/ip/<name>/:

<name>/
  rtl/<name>.sv           # RTL source
  tb/tb_<name>.sv         # Self-checking testbench
  formal/<name>_props.sv  # SVA properties
  formal/<name>.sby       # SymbiYosys config
  block.yaml              # Metadata
  README.md               # Usage guide

Add Flow

When user says "add a FIFO" or runs /gf-ip add fifo_sync:

1. Read block.yaml for metadata and parameters
2. Copy RTL to rtl/ (or user-specified directory)
3. Copy testbench to tb/
4. Copy formal properties to formal/
5. Update .gateflow/project.yaml — add to ip_blocks
6. Show instantiation example from README.md

Block Metadata Schema (block.yaml)

name: fifo_sync
version: 1.0.0
description: Synchronous FIFO with parameterized width and depth
parameters:
  WIDTH: { type: int, default: 8, description: "Data width in bits" }
  DEPTH: { type: int, default: 16, description: "FIFO depth (entries)" }
ports:
  - { name: clk, dir: input, width: 1 }
  - { name: rst_n, dir: input, width: 1 }
  - { name: wr_en, dir: input, width: 1 }
  - { name: wr_data, dir: input, width: WIDTH }
  - { name: rd_en, dir: input, width: 1 }
  - { name: rd_data, dir: output, width: WIDTH }
  - { name: full, dir: output, width: 1 }
  - { name: empty, dir: output, width: 1 }
formal_proofs:
  - p_no_overflow: "FIFO never accepts writes when full"
  - p_no_underflow: "FIFO never allows reads when empty"
dependencies: []

Instantiation Examples

fifo_sync

fifo_sync #(.WIDTH(8), .DEPTH(32)) u_fifo (.clk(sys_clk), .rst_n(sys_rst_n), .wr_en(wr_valid && !fifo_full), .wr_data(wr_data), .rd_en(rd_consume), .rd_data(rd_out), .full(fifo_full), .empty(fifo_empty));

fifo_async

fifo_async #(.WIDTH(32), .DEPTH(16)) u_cdc (.wr_clk(clk_fast), .wr_rst_n(rst_fast_n), .wr_en(producer_valid), .wr_data(producer_data), .wr_full(full), .rd_clk(clk_slow), .rd_rst_n(rst_slow_n), .rd_en(consumer_ready), .rd_data(consumer_data), .rd_empty(empty));

cdc_2ff

cdc_2ff u_sync (.clk(clk_dst), .rst_n(rst_dst_n), .d(async_signal), .q(synced_signal));

uart

uart #(.CLK_FREQ(100_000_000), .BAUD_RATE(115200)) u_uart (.clk, .rst_n, .tx_data(tx_byte), .tx_valid(tx_start), .tx_ready(tx_idle), .tx(uart_tx_pin), .rx(uart_rx_pin), .rx_data(rx_byte), .rx_valid(rx_ready));

spi_master

spi_master #(.CLK_DIV(8)) u_spi (.clk, .rst_n, .cpol(1'b0), .cpha(1'b0), .tx_data(spi_tx), .tx_valid(spi_start), .tx_ready(spi_idle), .rx_data(spi_rx), .rx_valid(spi_done), .sclk(spi_sclk), .mosi(spi_mosi), .miso(spi_miso), .cs_n(spi_cs_n));

IP Block Comparison

Need	Use	Not	Why
Same-clock buffering	fifo_sync	fifo_async	Async has Gray code overhead
Cross-domain stream	fifo_async	cdc_2ff	2FF only handles 1-bit
Cross-domain 1-bit flag	cdc_2ff	fifo_async	FIFO overkill for 1-bit
Cross-domain multi-bit (infrequent)	cdc_handshake	fifo_async	Handshake smaller
Cross-domain multi-bit (streaming)	fifo_async	cdc_handshake	Handshake blocks

GATEFLOW-RESULT Format

---GATEFLOW-RESULT---
STATUS: PASS | FAIL | NEEDS_ACTION
OPERATION: add | list | info
BLOCK: <name>
VERSION: <version>
FILES: [copied files]
DETAILS: [summary]
---END-GATEFLOW-RESULT---