Texas Instruments TLV320AIC12KEVMB-K appendix USB-MODEVM Protocol, Setreport

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Figure 16. Help

The actual USB protocol used as well as instructions on writing scripts are detailed in the following subsections. While it is not necessary to understand or use either the protocol or the scripts directly, understanding them may be helpful to some users.

6.9.1USB-MODEVM Protocol

The USB-MODEVM is defined to be a Vendor-Specific class, and is identified on the PC system as an NI-VISA device. Because the TAS1020 has several routines in its ROM which are designed for use with HID-class devices, HID-like structures are used, even though the USB-MODEVM is not an HID-class device. Data passes from the PC to the TAS1020 using the control endpoint.

Data is sent in an HIDSETREPORT (see Table 7):

Table 7. USB Control Endpoint

HIDSETREPORT Request

PART	VALUE	DESCRIPTION
bmRequestType	0x21	00100001
bRequest	0x09	SET_REPORT
wValue	0x00	don't care
wIndex	0x03	HID interface is index 3
wLength	calculated by host
Data		Data packet as described
		below

22	TLV320AIC12KEVMB-K and TLV320AIC14KEVMB-K User's Guide	SLAU229B–October 2007–Revised August 2008
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