Visible to Intel only — GUID: iga1401396007005
Ixiasoft
Visible to Intel only — GUID: iga1401396007005
Ixiasoft
24.2.4. Avalon® -ST Sink to Avalon® -MM Read Agent
An Avalon® -MM host reads the data from the FIFO core. The signals are mapped into bits in the Avalon® address space. If Allow backpressure is turned on, the input (sink) interface uses the ready and valid signals to indicate when space is available in the FIFO core and when valid data is available. For the output interface, waitrequest is asserted for read operations when there is no data to be read from the FIFO core. It is deasserted when the FIFO core has data to send. The memory map for this configuration is exactly the same as for the Avalon® -MM to Avalon® -ST FIFO core. See the for Memory Map table for more information.
If Enable packet data is turned off, read data repeatedly at address offset 0 to pop the data from the FIFO core.
If Enable packet data is turned on, the Avalon® -MM read host starts reading from address offset 0. If the read is valid, that is, the FIFO core is not empty, both data and packet status information are popped from the FIFO core. The packet status information is obtained by reading at address offset 1. Reading from address offset 1 does not pop data from the FIFO core. The ERROR, CHANNEL, SOP, EOP and EMPTY fields are available at address offset 1 to determine the status of the packet data read from address offset 0.
The EMPTY field indicates the number of empty symbols in the data field. For example, if the Avalon® -ST interface has symbols-per-beat of 4, and the last packet data only has 1 symbol, the empty field is 3 to indicate that 3 symbols (the 3 least significant symbols in the memory map) are empty.