Altera RapidIO MegaCore Function - Manual (Page 80)

4–34 Chapter 4: Functional Description
Logical Layer Modules
RapidIO MegaCore Function August 2014 Altera Corporation
User Guide
■ “Input/Output Avalon-MM Master Module”
■ “Input/Output Avalon-MM Slave Module” on page 4–41
Input/Output Avalon-MM Master Module
The Input/Output (I/O) Avalon-MM master Logical layer module receives RapidIO
read and write request packets from a remote endpoint through the Transport layer
module. The I/O Avalon-MM master module translates the request packets into
Avalon-MM transactions, and creates and returns RapidIO response packets to the
source of the request through the Transport layer.
Figure 4–17 shows a block diagram
of the I/O Avalon-MM master Logical module and its interfaces.
1
The I/O Avalon-MM master module is referred to as a master module because it is an
Avalon-MM interface master.
To maintain full-duplex bandwidth, two independent Avalon-MM interfaces are used
in the I/O master module—one for read transactions and one for write transactions.
The I/O Avalon-MM master module can process a mix of as many as seven NREAD or
NWRITE_R
requests simultaneously. If the Transport layer module receives an NREAD or
NWRITE_R request packet while seven requests are already pending in the I/O
Avalon-MM master module, the new packet remains in the Transport layer until one
of the pending transactions completes.
Figure 4–17. I/O Master Block Diagram
Transport Side
TX
Interface
32 or 64 bits
Transport Side
RX
Interface
32 or 64 bits
Tx
Sink
Source
Read
Master
Write
Master
io_m_rd_readdata
io_m_rd_readdatavalid
io_m_rd_read
io_m_rd_waitrequest
io_m_rd_address
io_m_rd_burstcount
io_m_rd_readerror
io_m_wr_writedata
io_m_wr_write
io_m_wr_waitrequest
io_m_wr_address
io_m_wr_burstcount
io_m_wr_ byteenable
Rx
Datapath Read
Avalon-MM Interface
32 or 64 bits
Datapath Write
Avalon-MM Interface
32 or 64 bits