usb_msc_device Directory Reference

Directory dependency graph for usb_msc_device:

Directories
	src

Detailed Description

USB Mass Storage smoke test on USB-FS. The board enumerates as a removable drive backed by a blank RAM disk with no filesystem on it, so the host formats it; the USBX device storage class serves the BOT/SCSI transport and the app supplies the RAM-backed read, write and status hooks. It is the scaffold the MRAM storage apps are built on.

It is manual because the proof is a human formatting the disk from a PC, writing a file, unmounting, remounting, and finding the file still there.

Linux tolerating a defect is not evidence of conformance

Getting macOS to accept the device took two first-party fixes that the Linux path had happily ignored:

• The vendored USBX INQUIRY handler reports RESPONSE DATA FORMAT 0 (SCSI-1) and ignores the EVPD bit. macOS answers that with a Bulk-Only Mass Storage Reset and abandons the device. It is replaced by a first-party override under port/usbx/ that reports SPC-2 and serves VPD pages 0x00 and 0x80.
• The device-controller bridge gained strand recovery for stashed bulk-IN transfers (a NAK PID with a bank already loaded) and a transactional BEMPSTS acknowledgement for multi-packet IN streaming. The JLink-readable BOT event trace ring added alongside is what made the failure visible at all.

The USB IDs come from the pid.codes free-for-experiments range and are bench-only – nothing here is a registered product. LED2 toggles as the class runs (EK-RA8D2 v1 UM Table 24 p 31).