USB, Hydra, F411 - deep dive 2025

I began this exercise in February of 2025 and am still going in April. At some point I will return the the entirely different USB hardware on the STM32F103. I am also now working with other F4xx boards like the STM32F429, as you will discover below.

The bulk of this page is in chronological order, which allows people who are following what I do to simply check the end of this page for new material. Some general material is up front.

General material

• Pico and USB
• Names and history
• USB connector durability
• Things to do in future investigations

Chronological essays

• Remembering how to work with one of these
• Old Hydra - part 1 - run it
• Old Hydra - part 2 - review my notes
• Old Hydra - part 3 - the plot thickens
• Old Hydra - part 4 - reading data
• Some planning
• some Comments on the 'duino source code
• F411 USB hardware -- addresses
• F411 USB hardware -- endpoints
• Initialization
• Callbacks - the USR_cb structure
• Callbacks - the USBD_DCD_INT_cb structure
• Callbacks - more callbacks!
• Enumeration - part 1
• Enumeration - part 2
• Enumeration - part 3 - documents and terminology
• Rearrange some BSP routines
• Enumeration - part 4 - run code with debug enabled
• VBUS sensing

• Cscope - sharpening the saw
• Cscope - my tutorial
• Cscope - my notes on using it with vim

• USB endpoints - part 1
• USB endpoints - part 2
• USB endpoints - part 3 - writing
• USB endpoints - part 4 - writing, and experiment
• NVIC - interrupts on the STM32
• USB endpoints - part 5 - reading
• USB endpoints - part 6 - experiments reading
• USB interrupts
• USB endpoints - part 7 - more on reading

• USB class interface - VCP
• Include file hell
• Tidy up the source code - part 1
• Tidy up the source code - part 2
• Bad cable
• What are these interface requests

• USB on the STM32F407
• Output during FS enumeration
• Run the other (HS) usb on the F407
• Output during HS enumeration
• Sharks and ttyUSB

• Fxxx USB hardware -- another look

• Giving the code the Kondo treatment