USB Command Code
| RESERVED | Reserved, user software should not write ones to reserved bits. The value read from a reserved bit is not defined. |
| CMD_PHASE | Command phase action 1 (WRITE): Write 2 (READ): Read 5 (COMMAND): Command |
| CODE_WDATA | This is a multi-purpose field. When CMD_PHASE is Command or Read, this field contains the code for the command (CMD_CODE). When CMD_PHASE is Write, this field contains the command write data (CMD_WDATA). |
| RESERVED | Reserved, user software should not write ones to reserved bits. The value read from a reserved bit is not defined. |