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Kit Operation
6.16.1
USB-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 is passed from the PC to the TAS1020 using the control endpoint.
Data is sent in an HIDSETREPORT (see
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
The data packet consists of the following bytes, shown in
Table 8. Data Packet Configuration
BYTE NUMBER
TYPE
DESCRIPTION
0
Interface
Specifies serial interface and operation. The two values are logically OR'd.
Operation:
READ
0x00
WRITE
0x10
Interface:
GPIO
0x08
SPI_16
0x04
I2C_FAST
0x02
I2C_STD
0x01
SPI_8
0x00
1
I
2
C Slave Address
Slave address of I
2
C device or MSB of 16-bit reg addr for SPI
2
Length
Length of data to write/read (number of bytes)
3
Register address
Address of register for I
2
C or 8-bit SPI; LSB of 16-bit address for SPI
4..64
Data
Up to 60 data bytes could be written at a time. EP0 maximum length is 64. The
return packet is limited to 42 bytes, so advise only sending 32 bytes at any one
time.
Example usage:
Write two bytes (AA, 55) to device starting at register 5 of an I
2
C device with address A0:
[0] 0x11
[1] 0xA0
[2] 0x02
[3] 0x05
[4] 0xAA
[5] 0x55
TLV320AIC33EVM and TLV320AIC33EVM-PDK User's Guide
36
SBAU114 – November 2005