ULX3S / Hazard3-Doom

Device Tool

Not connected

Device uploading

FPGA, console firmware, Doom application, and IWAD loading tools.

FPGA / Firmware / Doom
FPGA web flasher ULX3S US1 / JTAG

Program Hazard3-Doom from the browser

Uses WebUSB to drive the ULX3S FT231X JTAG interface directly. This first version programs FPGA SRAM from a Hazard3-Doom .bit file or an SVF file, so the image is temporary and is lost when the board powers off.

USB/JTAG Not connected FPGA Not probed Docs
Before programming Use the ULX3S US1 USB connector. Close fujprog, OpenOCD, and other programs using US1. The browser derives or verifies the ECP5 target ID before programming.
Idle
Flasher log 


                        
Persistent SPI flash is intentionally not written by this first implementation. Verify browser/JTAG programming on both ULX3S 12F and 85F before enabling a permanent-flash workflow.

                    

                


                

                    Console firmware uploader Local GDB / OpenOCD
                    

                        

                            

                                
Load the Hazard3 console firmware

                                
Select hazard3-boot-monitor.elf. The local web server passes the ELF to the existing GDB loader, which halts Hazard3 through OpenOCD, writes and verifies the ELF sections, sets _start, and resumes the core.

                            

                            

                                Local loader
                                
                                    Checking...
                                    (source)
                                
                                OpenOCD
                                Must already listen on port 3333. See tips
                            

                        


                        

                            

                            

                                Load flow
                                1. Program the matching FPGA bitstream.
                                2. Disconnect the browser FPGA flasher from US1.
                                3. Start OpenOCD with the matching board configuration.
                                4. Select the RISC-V ELF and load it.
                            

                        


                        

                            
                        


                        

                            
                            Checking local loader...
                        


                        


                        
The firmware does not need a self-replacement listener for this path. OpenOCD and GDB load it through the Hazard3 debug module. This control is available only when the page is served by web/web-server.py, not from GitHub Pages or a generic static HTTP server.

                    

                


                

                    Doom H3D uploader UART / H3L
                    

                        

                            

                                
Load a Doom image over UART

                                
Select a packaged .h3d image and send it directly to the resident monitor. The browser validates the H3D header and payload CRC32 before transfer. This loads SDRAM only; it does not modify the SD card.

                            

                            

                                Protocol
                                H3L over Web Serial
                                Monitor
                                Use from the > prompt
                            

                        


                        

                            

                            

                                Upload flow
                                1. Connect the UART terminal.
                                2. Stop Doom first if it is currently running.
                                3. Select a valid packaged H3D image.
                                4. Upload; the browser performs the H3L READY/DATA/OK handshake.
                                
                            

                        


                        

                            
                        


                        

                            
                            Idle
                        


                        
The H3L loader must own the UART. If Doom is running, use Stop Doom first and wait for the resident monitor > prompt before uploading.

                    

                


                

                    Doom IWAD uploader UART / H3W
                    

                        

                            

                                
Load a Doom IWAD over UART

                                
Select a legally obtained .wad file and send it to the resident monitor's reserved SDRAM IWAD region. The browser validates the IWAD header, directory, lump bounds, filename, and CRC32 before transfer.

                            

                            

                                Protocol
                                H3W over Web Serial
                                Monitor
                                Use from the > prompt
                            

                        


                        

                            

                                Doom IWAD (.wad)
                                
                                No IWAD selected
                                
                                

                                    
                                    
                                

                            


                            

                                Upload flow
                                1. Connect the UART terminal.
                                2. Stop Doom first if it is currently running.
                                3. Select an IWAD and the memory profile matching the monitor build.
                                4. Upload; the browser performs the H3W READY/DATA/OK handshake.
                                
                            

                        


                        

                            
                        


                        

                            
                            Idle
                        


                        
IWAD files are not included with Hazard3-Doom. Use a legally obtained IWAD. The selected memory profile must match the resident monitor build because the H3W header contains the SDRAM load address.

                    

                

            

        


        

            
                

                    
Serial connection

                    
Direct browser connection using the Web Serial API.

                

                Web Serial
            
            

                

                    
                    
                    
                    
                    
                    
                


                

                    
                    
                


                
            

        


        

            

                

                    
UART terminal

                    
No serial port selected.

                

                

                    
                    
                    
                    
                    
                        
                    
                    
                

            


            


            

                
                
                
            


            

                RX 0 bytes
                TX 0 bytes
                00:00:00
            

        


        

            

                

                    
Hazard3-Doom controls

                    
Convenience controls for the resident monitor. Line commands use the selected line ending; raw monitor keys are sent as one byte.

                

            


            

                

                    Monitor
                    

                        
                        
                        
                        
                        
                        
                    

                


                

                    SAO / I2C
                    

                        
                        
                        
                        
                        
                    

                


                

                    I2CDriver GUI keys
                    
Single-byte controls for the interactive i2c gui screen; no CR/LF is appended.

                    

                        
                        
                        
                        
                        
                        
                        
                        
                        
                        
                    

                


            


            

                
                

                    
                    
                

                
The custom command is saved only in this browser.