# Host Interface Module (HIM)¶

The Host Interface Module (HIM) converts the debug packets to a length-value encoded data stream, that is transferred using the glip interconnect. This format is simple and contains the length of the debug packet in one data item followed by the debug packet.

Alternatively, the HIM can be configured to store the debug packets to the system memory using the memory interface.

## Debug Transport Datagram (DTD)¶

Todo

Do we really want to specify this format in here, or should we leave it as implementation-defined until we find a better solution which can cope with variable-length data in a streaming fashion (i.e. without buffering the whole packet first to determine its length)?

The Debug Transport Datagram (DTD) encapsulates the Debug Packet into a 16-bit wide packet. The Debug Packet data is prepended with the size of the packet in 16 bit words.

Table 18 Debug Interconnect Packet (DI Packet) Structure
word index data
0 size n of the Debug Packet in 16 bit words
1 word 0 of the Debug Packet
2 word 1 of the Debug Packet
n + 1 word n of the Debug Packet

Note

Due to the native width the Debug Transport Datagram is used when transferring a Debug Packet off-chip.