Calculator User Manual

6.9.1 USB-MODEVM Protocol
Kit Operation www.ti.com
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.
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
TLV320AIC12KEVMB-K and TLV320AIC14KEVMB-K User's Guide22 SLAU229B – October 2007 – Revised August 2008
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