tinyusb.git/examples/device, branch claude/audio-fifo-priming

audio_test_freertos: prime and hold the EP IN FIFO at its threshold

2026-08-28T18:08:56Z

The 1 ms producer tick and host SOF are independent clocks. Writing one frame per tick from stream open leaves the FIFO within a frame of empty for ~180 ms (flow control climbs ~1.5 B/ms), and on underrun the driver replays the previous packet's tail (hfp HIL: 'expected 8702, got 8696' - exactly one HS packet of 6 samples back). Hold the FIFO at the driver's own flow-control threshold instead: primed at open, topped up per tick, each write still requiring a full frame of room so the overwritable FIFO never drops samples. Filling above threshold is deliberately avoided - it parks flow control at max-size packets (48.73 kHz) and overruns the host capture. Verified by simulating the driver's control law over the 2 s capture: zero underruns at +/-400 us jitter vs 3 events before. The driver-side half (audiod_tx_xfer_isr ignoring a short tu_fifo_read_n and submitting stale bytes) is docs/superpowers/followup/pr3851-audiod- short-fifo-read.md, for its own PR.

ci: an empty selection must build nothing, plus selector follow-ups (#3845)

2026-08-25T02:46:42Z

ci: an empty selection must build nothing, plus selector follow-ups A PR whose build axis legitimately selected nothing rebuilt everything. build.yml reads .build.families twice - as a |-joined regex, and implicitly as "is anything selected" - but tested only -z "$FAMILY_REGEX", which an empty list and a charset-rejected one both satisfy while meaning opposite things. ci_set_matrix had already returned the correct all-empty matrix; the fall-open branch discarded it. #3842 and #3840 each spent 74 cmake legs on it. Branch on the two cases instead, rename FAM_* to FAMILY_*, and cover the block with a test that extracts it from build.yml and executes it - it had no test at all, which is how this shipped through two merges. Follow-ups to the same machinery: glob.escape the repo root at five sites, so a checkout path containing [ or * stops failing closed; drop the ci-full label, read after the matrix was already computed and so never functional; delete 13 mcu:MKL25ZXX / mcu:SAME5X skip tokens matching no board; carry the rule table in the module docstring, guarded against drift; and pin six selection behaviours a mutation pass proved untested. Cut the selector's cost 1.8x (26.0s -> 14.6s) with 0 divergences over 260 paths, and stop scoping the membrowse upload by the PR example filter.

examples: document and work around the i.MX RT and LPC55 USB errata

2026-08-18T15:07:49Z

ERR050101: while an isochronous IN endpoint is active, an IN token addressed to that same endpoint number on ANOTHER device sharing the host can silently unprime one of this device's OUT endpoints - control, bulk, interrupt or isochronous alike. NXP states it cannot be detected by software and raises no interrupt, so the endpoint simply stops answering and the transfer never completes. The workaround is a uniqueness requirement rather than a particular number: the isochronous IN endpoint must not share its number with any IN endpoint in use on the bus. One family-wide constant therefore defeats it, since two affected boards on the same hub then pick the same number and each becomes the other's aggressor. CFG_TUSB_MIMXRT1XXX_ERRATA_ERR050101 is set only for the parts whose errata list it - RT1015, RT1020, RT1024 and RT1050, where it is marked no fix scheduled, plus RT1060 and RT1064 rev A - so RT1010 and the RT11xx family keep the ordinary number and cannot collide with an affected board beside them. Several affected boards on one hub can still be given distinct numbers with -DEPNUM_ISO_IN. The guard covers every example that has an isochronous IN endpoint: audio_test, audio_4_channel_mic, uac2_headset, cdc_uac2, usbtest, video_capture and video_capture_2ch. The video examples move the endpoint only when streaming isochronously, since the bulk configuration is unaffected, and video_capture_2ch takes two numbers because it has two streams. The macro name follows CFG_TUSB_RP2_ERRATA_E2/E4/E15 already in tree, and its is fixed, and which cannot be told apart at compile time - a way to define it to 0. device_issues.rst records ERR050101 against every affected part with a link to each errata sheet, and adds the LPC55S2x USB.3 speed-detection and USB.5 isochronous IN entries, neither of which TinyUSB works around. The branch's design notes are included under docs/superpowers. Verified: 340 wedge-free runs on mimxrt1064_evk, which previously wedged within hours, and the macro resolving to endpoint 0x87 on mimxrt1064_evk against 0x83 on mimxrt1010_evk and stm32f407disco.

example(midi2): report device identity in midi2_device

2026-08-14T18:21:24Z

Enable APM32F0 dependency fetching and CI

2026-07-25T03:28:29Z

misc fixes

2026-07-19T12:38:54Z

examples now build

2026-07-19T11:24:40Z

dcd_lpc17_40: address review findings in the iso paths

2026-07-17T17:15:53Z

From a second max-effort review of the branch: - Drop the dead TUSB_XFER_ISOCHRONOUS case in dcd_edpt_open: iso endpoints are armed via dcd_edpt_iso_alloc/activate (TUP_DCD_EDPT_ISO_ALLOC is defined for this IP), never through dcd_edpt_open, so the case and its dd->isochronous assignment were unreachable and asserted a false invariant. Only bulk/interrupt reach the switch now. - Extend the iso compile gate to the classes that actually arm an iso endpoint: DCD_ISO_ENABLED now includes CFG_TUD_BTH (bth_device.c opens an iso voice endpoint). Without it a BTH build would compile the iso machinery out and fail SET_INTERFACE at runtime. - Un-skip LPC175X_6X in the usbtest example: it shares dcd_lpc17_40.c with LPC40XX verbatim, so the "DCD has no isochronous support" skip reason no longer holds. Build-verified for lpcxpresso1769 (previously blocked by the skip). - TU_ATTR_UNUSED on the ep_id_is_iso helper: every caller is under #if DCD_ISO_ENABLED, so non-iso builds don't reference it and clang's -Wunused-function (fatal in CI) rejected the build — gcc stays quiet. Verified with the full lpc17 and lpc40 example sets under arm-clang. A fifth finding — bounding control_ep_read's PACKET_READY spin with a timeout — was implemented and REVERTED: a naive 100k-iteration bound fires on legitimately-slow control reads and intermittently drops the device (hardware-proven by interleaved A/B testing against the pre-fix binary). The infinite wait is retained; the read is only reached once out_received/ out_queued signal data is present, so the theoretical IRQ-off hang is not reachable in practice. Re-verified on ea4088_quickstart: usbtest 30/30 (repeated) + HIL 14/14.

skill: add usb-sniffer — wire-level capture with the ataradov hardware tap

2026-07-17T10:32:47Z

Fourth view in the USB debugging toolset (usbmon = host URBs, usb-debug = host reasoning, usb-target-debug = device firmware, usb-sniffer = what actually crossed D+/D-). Covers the ataradov/usb-sniffer analyzer: headless pcapng capture (--speed ls/fs/hs, --fold, --limit self-exit), Wireshark/tshark analysis recipes, and the wire realities that bite: downstream broadcast, sniffer self-capture noise, xHCI devnum != wire address, tap-point-dependent reset visibility (hub choreography anchors), FS-behind-HS-hub splits. Every recipe hardware-validated on the rig, including the capture-window floor (a 3 s window provably misses the enumeration ladder; 3M packets minimum). Two udev files with distinct audiences, not one: - examples/device/99-tinyusb-examples.rules (renamed from 99-tinyusb.rules): the user-facing rules the examples need — cafe VID access, hidraw, the ModemManager blacklist, a couple of board probes. getting_started.rst, the webusb_serial README and its source comment point here. - tools/88-tinyusb.rules: the HIL rig's private probe/analyzer allowlist, now with the sniffer (6666:6620 + blank FX2LP 04b4:8613). Installed on the rig only; the usb-sniffer skill references it.

dcd_lpc17_40: fix stale EP0 out_received, add isochronous support

2026-07-17T09:48:01Z

EP0 control-OUT fix (usbtest 14/21, errno 110/-74): usbd queues the status-stage OUT ZLP of every control read with buffer=NULL, so the ISR's `if (out_buffer)` check missed it and marked the arriving ZLP as out_received instead. The stale flag poisoned the next control-OUT with data: its first chunk "completed" instantly from an empty EP0 buffer and the host's real DATA NAKed forever. Track queued transfers with an explicit out_queued flag and void half-finished control state on a new SETUP. Isochronous support (UM10562 12.15.6): 5-word DMA descriptors with per-packet size memory, buflen/present_count in packets, one packet per FRAME (no DMARSet/EpIntEn involvement), completion at EOT for both directions. Details that matter: - the iso machinery (5th DD word + packet-size memory) is compiled only when an iso-capable class is enabled (CFG_TUD_AUDIO/VIDEO/VENDOR), so non-iso builds pay nothing: _dcd stays 648 B vs 1032 B with iso - ISR dispatch keys on the hardware's fixed ep-number/type map (ep_id_is_iso), never on dd fields that thread mode rebuilds - iso OUT honors Packet_valid (bit 16) and prefills the hardware writeback slots with 0, so a missed frame counts as 0 bytes instead of reading back stale buffer contents as data - packet count is validated (tu_div_ceil <= ISO_MAX_PACKETS) before the DD is touched, so an oversized transfer is refused without leaving a serviceable half-built descriptor armed for the frame engine - dcd_edpt_iso_alloc and iso_activate both enforce the fixed iso endpoint numbers (3/6/9/12); classes ignore alloc's return value, so activate must not trust it Un-skip LPC40XX in the usbtest example; tier 4 now enumerates and passes iso cases 15/16/22/23. cdc_msc_throughput and printer_to_cdc had bulk on iso-only EP3 (SET_CONFIGURATION failed with -32); add the LPC17/40 EPNUM block (bulk on EP2/EP5) like other fixed-EP examples. Verified on ea4088_quickstart: usbtest tier-4 battery 30/30 repeatedly and the full device HIL suite 14/14 (incl. audio_test iso).