ULX3S / Hazard3-Doom

UART Console

Not connected

Serial connection

Direct browser connection using the Web Serial API.

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
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.

                

            


            

                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.

                

            

        


        

            

                

                    
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.