Design a Lattice FPGA HDMI Transmission Scheme

Here's a comprehensive Lattice FPGA HDMI Transmission Scheme design using low-power Lattice FPGAs (e.g., ECP5 or CrossLink-NX). This solution covers hardware, FPGA logic, and software components for robust HDMI signal transmission: 1. System Overview Target Devices: Lattice ECP5 (for cost-sensitive designs) or CrossLink-NX (for embedded MIPI DSI/CSI-to-HDMI bridging) HDMI Version: 1.4b (Supports 1080p60, with optional TMDS scrambling for EMI reduction) Key Features: TMDS Signal Generation (FPGA-native or external PHY) EDID Management (Hot-Plug Detect, DDC I2C) Color Space Conversion (RGB ↔ YCbCr 4:4:4) Audio Embedding (I2S to HDMI Audio Packet) 2. Hardware Design A. Block Diagram [Video Source] → [Lattice FPGA] → [HDMI Transmitter] → [HDMI Connector] (ECP5/CrossLink) (e.g., IT66121 or native TMDS) B. Critical Components FPGA Selection: ECP5-85F (For 1080p60 with internal LVDS→TMDS conversion) CrossLink-NX-17 (For MIPI DSI/CSI to HDMI conversion) HDMI PHY Options: Internal TMDS (ECP5 LVDS pins + SERDES) External PHY (e.g., IT66121 for simplified design) Clock Architecture: 148.5 MHz for 1080p60 (Pixel Clock) 27 MHz for I2C/EDID management Optional PLL for audio clock (e.g., 12.288 MHz for 48kHz audio) Connectors: HDMI Type A (Standard 19-pin) ESD Protection (TVS diodes on TMDS lines) 3. FPGA Logic Design (Verilog/VHDL) A. TMDS Encoder Core verilog module tmds_encoder ( input clk_pixel, input [7:0] data, input [1:0] control, output [9:0] tmds ); // Implement DVI 1.0 Spec TMDS encoding // Includes XOR/XNOR reduction and DC balancing endmodule B. Video Timing Controller verilog module video_timing ( output [11:0] h_count, output [11:0] v_count, output h_sync, v_sync, data_enable ); // Generates 1080p60 timing: // Active: 1920x1080, Front Porch/Sync/Back Porch endmodule C. I2C EDID Handler verilog module edid_reader ( inout sda, output scl, input hpd, output [7:0] edid_data ); // Responds to DDC requests and serves EDID // Implements I2C slave at address 0x50 endmodule 4. Software Components A. Lattice Diamond/Primary Configuration Pin Constraints (.lpf file for ECP5): LOCATE COMP "tmds_clk_p" SITE "E4"; IO_TYPE "LVDS25"; PLL Configuration: Generate 148.5 MHz from 25 MHz oscillator Phase-align TMDS clock/data B. Embedded RISC-V Core (For Smart HDMI) Use Lattice Propel to add soft-core CPU for: EDID parsing Dynamic resolution switching Audio packet generation 5. Signal Integrity Considerations PCB Layout Rules: TMDS Differential Pairs: 100Ω impedance, length-matched (±50mil) Layer Stackup: Route on adjacent layers with ground plane Termination: On-die termination (ODT) in ECP5 EMI Reduction: Enable TMDS scrambling (HDMI 1.3+) Spread-spectrum clocking (if supported by sink) 6. Testing & Validation Test Pattern Generator: Implement color bars/ramp in FPGA logic verilog case (h_count[3:0]) 0: {r,g,b} = 8'hFF; // White 1: {r,g,b} = 8'h00; // Black // ... Color pattern endcase Compliance Testing: Use HDMI analyzer (e.g., Quantum Data) Verify: TMDS eye diagram EDID response time (

[Video Source] → [Lattice FPGA] → [HDMI Transmitter] → [HDMI Connector]
                   (ECP5/CrossLink)   (e.g., IT66121 or native TMDS)

verilog

module tmds_encoder (
  input clk_pixel,
  input [7:0] data,
  input [1:0] control,
  output [9:0] tmds
);
  // Implement DVI 1.0 Spec TMDS encoding
  // Includes XOR/XNOR reduction and DC balancing
endmodule

verilog

module video_timing (
  output [11:0] h_count,
  output [11:0] v_count,
  output h_sync, v_sync, data_enable
);
  // Generates 1080p60 timing:
  // Active: 1920x1080, Front Porch/Sync/Back Porch
endmodule

verilog

module edid_reader (
  inout  sda,
  output scl,
  input  hpd,
  output [7:0] edid_data
);
  // Responds to DDC requests and serves EDID
  // Implements I2C slave at address 0x50
endmodule

LOCATE COMP "tmds_clk_p" SITE "E4";
IO_TYPE "LVDS25";

verilog

case (h_count[3:0])
  0: {r,g,b} = 8'hFF; // White
  1: {r,g,b} = 8'h00; // Black
  // ... Color pattern
endcase

verilog

audio_packetizer u_audio (
  .i2s_data(audio_data),
  .hdmi_header(audio_header),
  .data_island(packet_data)
);

tcl

reveal_insert -port h_sync -name h_sync_debug
reveal_trigger -condition {h_count == 0}

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