Device Descriptor

A device MUST expose a descriptor that is read by the controller following a soft reset and that is incorporated into the device table. The descriptor must contain the following information:

uint32    device_id
uint32    device_ver
uint32    rd_samp_size
uint32    wr_samp_size

• device_id: Device ID.

• device_ver: Device version. A version number to distinguish between implementations of a singular device type. Different versions MUST NOT change the device’s sample data format or alter an existing register map. However, register additions that do not affect the existing register map are allowed. Any change that warrants a modification of a device’s streaming data format, read size, write size, or existing register map MUST be implemented as a new Device ID.

• rd_samp_size: Read sample size. The length in bytes of a single device sample produced by the device and sent to the read stream. This value must be at least as a large as the number of bytes in the Device Sample indicated by the Read Frame Format.

• wr_samp_size: Write sample size. The length in bytes of a single device sample consumed by the device from the write stream.This value must be at least as a large as the number of bytes in the Device Sample indicated by the Write Frame Format.