usb_msc_mram Directory Reference

Directory dependency graph for usb_msc_mram:

Directories
	inc
	src

Detailed Description

Plug the board's USB-FS port into any computer and the chip's on-board MRAM shows up as a file. The board enumerates as a mass-storage device whose single LUN is a synthesized read-only FAT16 volume: the boot sector, FAT and root directory are generated on the fly inside the media-read callback, and the data clusters map 1:1 onto the MRAM code window at 0x02000000. The root holds one file, MRAM.BIN – open or copy it and you are reading the chip's own flash, live.

The LUN reports write-protected via MODE SENSE and rejects WRITE(10) with DATA PROTECT sense, so hosts mount it read-only and the MRAM is never touched. It is built on the same ThreadX + USBX storage scaffold as usb_msc_device; usb_msc_mram_hs is the high-speed twin.

The synthesized data region is padded well past the end of the file so that the cluster count crosses the FAT16 threshold of 4085 clusters (MS FAT spec 1.03 sec 3.5) – below it the volume is FAT12 and hosts reject the geometry.

It is manual, and the check worth doing by hand is the honest one: copy MRAM.BIN off over USB, dump the same window over SWD with the debugger's savebin, and compare. Identical bytes mean the whole path – FAT synthesis, SCSI, the device-controller bridge, the host – is telling the truth. LED1 toggles per SCSI read (EK-RA8D2 v1 UM Table 24 p 31).