Texas Instruments TLV320AIC3109EVM-K, Руководство пользователя

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56 SLAU738 – September 2017
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USB-MODEVM Protocol
Appendix I
SLAU738 – September 2017
USB-MODEVM Protocol
I.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 12 ):
Table 12. 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 in Table 13 .
The data packet consists of the following bytes, shown in Table 13 and the following paragraphs:
Table 13. Data Packet Configuration
Byte Number Type Description
0 Interface Specifies serial interface and operation. The two values are logically ORed.
Operation:
READ
WRITE 0x00
0x10
Interface:
GPIO
SPI_16
I2C_FAST
I2C_STD
SPI_8 0x08
0x04
0x02
0x01
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.