Altera RapidIO MegaCore Function - Manual (Page 77)

Chapter 4: Functional Description 4–31
Logical Layer Modules
August 2014 Altera Corporation RapidIO MegaCore Function
User Guide
■ For a MAINTENANCE write, converts the received request packet to an Avalon write
and presents it across the Maintenance Avalon-MM master interface.
■ Performs accounting related to the received RapidIO MAINTENANCE read or write
operation.
■ For each MAINTENANCE request packet received from remote endpoints, generates a
Type 8 Response packet and presents it to the Transport layer for transmission.
The Avalon-MM master interface supports the following Avalon transfers:
■ Single master write transfer
■ Pipelined master read transfers
f
Refer to Avalon Interface Specifications for details on the supported transfers.
Figure 4–15 shows the signal relationships for a sequence of four write transfers on
the Maintenance Avalon-MM master interface.
Figure 4–16 shows the signal relationships for a sequence of three read requests
presented on the Maintenance Avalon-MM master interface.
When a MAINTENANCE packet is received from a remote device, it is first processed by
the Physical layer. After the Physical layer processes the packet, it is sent to the
Transport layer. The Maintenance module receives the packet on the Rx interface. The
Maintenance module extracts the fields of the packet header and uses them to
compose the read or write transfer on the Maintenance Avalon-MM master interface.
The following packet header fields are extracted:
■ ttype
Figure 4–15. Write Transfers on the Maintenance Avalon-MM Master Interface
4 8 C 10
ACACACAC 5C5C5C5C BEEFBEEF FACEFACE
mnt_m_write
mnt_m_writedata
mnt_m_address
mnt_m_waitrequest
sysclk
Figure 4–16. Timing of a Read Request on the Maintenance Avalon-MM Master Interface
mnt_m_read
mnt_m_address
mnt_m_readdatavalid
mnt_m_readdata
system clock
0x10 0x14 0x18
mnt_m_waitrequest