CX3 Development Board Enumeration Process Analysis 1

One, the following analysis results are reference to the end of 15 development of the CX3 Development Board, the picture is as follows:

Second, the UVC Protocol capture tool uses the bus HOUND6.0, the enumeration process data is as follows:

Third, the first instruction in the analysis Get_cur, control the transmission mode, the instruction sequence is: A1 81 00 01 01 00 22 00. The control UVC protocol is as follows:

1th byte 0XA1: Specifies the data direction returned for the Development Board to the computer;

2nd byte of 0x81:brequest=get_cur;

3rd, 4 bytes wvalue=0x0100, high byte 01, representing the CS number;

5th, 6 bytes windex=0x0001, low byte 01, representing the VS number;

7th, 8 bytes wlength=0x0022, data length is 34 bytes, UVC1.1 specification is defined,

Iv. analysis of the 34 bytes in the red box in Figure II is as follows:

from xx to XX xx xx xx

3f XX XX E3

00 00

Control the Development Board of the program, explained as follows:

/* UVC Probe Control Setting-[email protected] */
uint8_t Const Gl1080pprobectrl[cx3_uvc_max_probe_setting] = {
0x00, 0x00,/* bmhint:no fixed parameters */
0x01,/* Use 1st Video format Index */
0x01,/* Use 1st Video Frame Index */
0x15, 0x16, 0x05, 0x00,/* Desired frame interval in 100ns = (1/30) x10^7 */
0x00, 0x00,/* key frame rate in key frame/video frame units */
0x00, 0x00,/* pframe rate in Pframe/key frame units */
0x00, 0x00,/* Compression quality control */
0x00, 0x00,/* Window size for average bit rate */
0x00, 0x00,/* Internal video streaming i/f Latency in MS */
0x00, 0x48, 0x3F, 0x00,/* Max video frame size in bytes = 1920x1080 x 2 */
0x00, 0x90, 0x00, 0x00,/* No. of bytes device can rx in single payload:36kb */
0x00, 0x60, 0xe3, 0x16,/* Device Clock */
0x00,/* Framing information-ignored for uncompressed format*/
0x00,/* Preferred Payload format version */
0x00,/* Minimum Payload format version */
0x00/* Maximum Payload format version */
};

CX3 Development Board Enumeration Process Analysis 1