5418b836d5
Class drivers: skip and account the SS endpoint companion descriptor in every descriptor walk (hid, midi, midi2, ecm_rndis, printer, mtp, usbtmc), via a shared usbd_skip_ss_ep_companion() helper in usbd_pvt.h (cdc/ncm already handled; vendor/dfu naturally tolerant). usbtmc buffer grows to 1024 at SS to satisfy its packet-multiple assert. bth/audio/video are left FS/HS-only (ISO-centric; ISO is unsupported on the CH569 dcd). usbd.h: new SS template macros TUD_HID_SS_DESCRIPTOR(+INOUT), TUD_MIDI_SS_DESCRIPTOR (+ DESC_EP_SS part), TUD_MIDI2_DESC_ALT1_EP_SS, TUD_PRINTER_SS_DESCRIPTOR, TUD_MTP_SS_DESCRIPTOR, TUD_USBTMC_BULK_SS_DESCRIPTORS/INT_SS_DESCRIPTOR, with _SS_DESC_LEN counterparts (bulk endpoints hardcode 1024, companion after every EP). Examples: 17 bulk/interrupt examples gain the full SS descriptor set (EP0 512/64 clamp, SS device descriptor bcdUSB 3.20 mps0=2^9, SS config with companions, BOS caps, speed-switched callbacks): cdc_dual_ports, cdc_msc_freertos, dfu, dfu_runtime, dynamic_configuration, hid_boot_interface, hid_composite(+freertos), hid_generic_inout, hid_multiple_interface, midi_test(+freertos), midi2_device, msc_dual_lun, mtp, printer_to_cdc, usbtmc, webusb_serial. msc_dual_lun is un-skipped for CH569 using read-only flash disks (16KB RAM can't hold two 8KB RAM disks, same as ch32v10x/v20x boards). Validation: full example sweep green for hydrausb3_v1 (SPEED=super, 19 device ELFs) and raspberry_pi_pico; wTotalLength == sizeof() verified for every SS configuration array in the built ELFs; ceedling 65/65; pre-commit clean; code-size delta +0.0% on rp2040 (SS code folds out on non-SS builds). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_019MRGjBT2NBkCoWwyDT4LaE
Dynamic Configuration
Demonstrates returning different device and configuration descriptors at enumeration time, selected by the on-board button. The button is sampled when the host requests the device descriptor, so the device enumerates as one of two completely different personalities depending on whether the button is held while plugging in.
What it does
- Reads the on-board button when the host fetches the device descriptor to choose the active configuration.
- Button not pressed — enumerates as CDC + MIDI:
- CDC echoes back received data (and appends a newline after each carriage return); prints a banner when the terminal connects.
- MIDI continuously plays a fixed note sequence, and drains/discards any incoming MIDI.
- Button pressed — enumerates as MSC: presents a small read/write FAT12 RAM disk containing a
README.TXTfile. - Blinks the on-board LED to reflect bus state: 250 ms unmounted, 1000 ms mounted, 2500 ms suspended.
USB Descriptors
Two alternate configurations are served, chosen by the button at enumeration.
Button not pressed (CDC + MIDI):
| Interface | Class driver |
|---|---|
| 0–1 | CDC (virtual serial) |
| 2–3 | MIDI |
Button pressed (MSC):
| Interface | Class driver |
|---|---|
| 0 | MSC (mass storage) |
Configuration
Notable tusb_config.h settings (both personalities share one config):
#define CFG_TUD_CDC 1
#define CFG_TUD_MSC 1
#define CFG_TUD_MIDI 1
#define CFG_TUD_CDC_RX_BUFSIZE (TUD_OPT_HIGH_SPEED ? 512 : 64)
#define CFG_TUD_CDC_TX_BUFSIZE (TUD_OPT_HIGH_SPEED ? 512 : 64)
#define CFG_TUD_MIDI_RX_BUFSIZE (TUD_OPT_HIGH_SPEED ? 512 : 64)
#define CFG_TUD_MIDI_TX_BUFSIZE (TUD_OPT_HIGH_SPEED ? 512 : 64)
#define CFG_TUD_MSC_EP_BUFSIZE 512
Building
CMake:
mkdir build && cd build
cmake -DBOARD=raspberry_pi_pico ..
cmake --build .
Make:
make BOARD=raspberry_pi_pico all
Try it
Plug the board in normally: a serial port and a MIDI device appear on the host. Now hold the on-board button while plugging in (or while resetting): the device instead enumerates as a removable drive with a README.TXT file. The two personalities use different product IDs so the host treats them as distinct devices.