maksyuki
3b6a925a51
- Created documentation for , , , and modules, detailing their functionality, parameters, and usage examples. - Implemented a script to ensure required headings and content are present in documentation files. - Developed to generate and update documentation pages from SystemVerilog declarations, ensuring consistency and completeness.
2.2 KiB
cdc_sync
| Property | Value |
|---|---|
| Kind | module |
| RTL source | rtl/cdc/cdc_sync.sv |
| Availability | Synthesizable RTL |
Summary
Multi-flop synchronizer for a control bit or independently encoded vector.
Functional Behavior
Multi-flop synchronizer for a control bit or independently encoded vector. It carries the declared control, event, or data contract through the stated synchronizer, handshake, or Gray-pointer mechanism. Endpoint reset discards in-flight data unless the page identifies an acknowledged warm-clear path.
Suitable Applications
Use for reset release, asynchronous control/data transfer, asynchronous queues, event notification, and CDC recovery.
Parameters
The declaration below is canonical; retain the RTL-enforced parameter range.
| Parameter | Declaration |
|---|---|
STAGE |
parameter int STAGE = 2 |
DATA_WIDTH |
parameter int DATA_WIDTH = 1 |
Interface Definition
module cdc_sync #(
parameter int STAGE = 2,
parameter int DATA_WIDTH = 1
) (
input logic clk_i,
input logic rst_n_i,
input logic [DATA_WIDTH-1:0] dat_i,
output logic [DATA_WIDTH-1:0] dat_o
);
Port Summary
| Signal | Direction | Declaration |
|---|---|---|
clk_i |
input |
input logic clk_i |
rst_n_i |
input |
input logic rst_n_i |
dat_i |
input |
input logic [DATA_WIDTH-1:0] dat_i |
dat_o |
output |
output logic [DATA_WIDTH-1:0] dat_o |
Integration and Use
Never use a simple synchronizer for arbitrary multi-bit data. Keep both endpoint clocks running after reset release and obey all ready/busy outputs.
cdc_sync #(
.STAGE(STAGE),
.DATA_WIDTH(DATA_WIDTH)
) u_cdc_sync (
.clk_i(clk_i),
.rst_n_i(rst_n_i),
.dat_i(dat_i),
.dat_o(dat_o)
);
Dependencies and Verification
The linked RTL source is the implementation authority and contains local assertions for unsupported
parameter combinations. See docs/design.md for repository-wide CDC, reset,
stream, and storage contracts, and docs/verification.md for the
verification matrix.