VDM Ports - 4.0 English

QDMA Subsystem for PCI Express Product Guide (PG302)

Document ID
PG302
Release Date
2022-05-20
Version
4.0 English
Table 1. VDM Port Descriptions
Port Name I/O Description
st_rx_msg_valid O Valid
st_rx_msg_data[31:0] O

Beat 1:

{REQ_ID[15:0], VDM_MSG_CODE[7:0], VDM_MSG_ROUTING[2:0], VDM_DW_LENGTH[4:0]}

Beat 2:

VDM Lower Header [31:0]

or

{(Payload_length=0), VDM Higher Header [31:0]}

Beat 3 to Beat <n>:

VDM Payload

st_rx_msg_last O Indicate the last beat
st_rx_msg_rdy I Ready.
Note: When this interface is not used, Ready must be tied-off to 1.

RX Vendor Defined Messages are stored in shallow FIFO before they are transmitted to output ports. When there are many back to back VDM messages, FIFO overflows and these messages are dropped. It is best to repeat VDM messages at regular intervals.