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Loopback transfers

When the TI-Nspire is connected to a computer, but Computer Link Software is not running, sending the Operating System from the menu of the document management screen make it act as if it was sending and receiving the OS at the same time. The storage memory consumption increases during the loopback transfer, as it does for a real OS upgrade. The same behavior appears when trying to send documents from there contextual menu. The received documents are copied with a new name that has numerical suffix. Loopback transfers don't seem to be faster than real ones, probably because nearly the whole connectivity stack is used, and the physical transfer is not what limits the speed.

No data is exchanged with the computer during a loopback transfer (USB analyzers don't report anything, and it works even when the TI-Nspire driver is not installed).


USB descriptors

Here is the interesting part (i.e. different from the TI-84 Plus and Titanium) of the USB descriptors advertised by the TI-NSpire in standard (not TI-84 Plus emulation) mode.

Device Descriptor:
	idProduct	E012h (reminder: E001 : Silverlink, E004: Titanium, E008: TI-84 Plus)
	bcdDevice	0100h // 1.00
	iProduct	      // "TI-Nspire(tm) Handheld"

Configuration Descriptor:
	bmAttributes	  80h // Bus Powered (Titanium: Self Powered Remote Wakeup)
	bMaxPower	  32h // 100 mA (Titanium: 0 mA)

OTG Descriptor // As on Titanium and TI-84 Plus

Interface descriptor: Vendor Specific class, 1 Bulk IN endpoint, 2 Bulk OUT endpoints
(was 1 Bulk IN and 1 Bulk OUT on Titanium/TI-84 Plus)

When a TI-84 Plus is emulated by the TI-Nspire, the descriptors are the same as a real TI-84 Plus except:

Device Descriptor:
	idProduct	E004h // Titanium!
	bcdDevice	0200h // 2.00 (Real TI-84 Plus: 1.10)
	iProduct	      // "TI-84 Plus Silver Edition (Emulation)"

Configuration Descriptor: // Same as the real TI-84 Plus
	bmAttributes	  C0h // Self Powered
	bMaxPower	  00h // 0 mA

Interface and enpoint descriptors: same as the TI-84 Plus (1 Bulk IN , 1 Bulk OUT)