Device - Altera Cyclone V User Manual

3–4

Device

Table 3–2
Table 3–2. Capabilities Registers for Function <n> (Part 1 of 2)
Possibl
Parameter
Values
128
bytes
Maximum
256
payload size
bytes,
0x084
512
bytes,
Number of tags
supported 32
supported per 64
function
ABCD
BCD
ABC
Completion
AB
timeout range
None
Cyclone V Hard IP for PCI Express
describes the shared device parameters.
Default
e
Value
Device Capabilities
128 bytes
32
ABCD
B
A
Description
Specifies the maximum payload size supported. This
parameter sets the read-only value of the max payload size
supported field of the Device Capabilities register (0x084[2:0])
and optimizes the IP core for this size payload.
Indicates the number of tags supported for non-posted
requests transmitted by the Application Layer. This parameter
sets the values in the Device Control register (0x088) of the
PCI Express Capability Structure described in
page 6–4.
The Transaction Layer tracks all outstanding completions for
non-posted requests made by the Application Layer. This
parameter configures the Transaction Layer for the maximum
number to track. The Application Layer must set the tag values
in all non-posted PCI Express headers to be less than this
value. Values greater than 32 also set the extended tag field
supported bit in the Configuration Space Device
Capabilities register. The Application Layer can only use
tag numbers greater than 31 if configuration software sets the
Extended Tag Field Enable bit of the Device Control
register. This bit is available to the Application Layer as
cfg_devcsr[8].
Indicates device function support for the optional completion
timeout programmability mechanism. This mechanism allows
system software to modify the completion timeout value. This
field is applicable only to Root Ports and Endpoints that issue
requests on their own behalf. Completion timeouts are
specified and enabled in the Device Control 2 register (0x0A8)
of the PCI Express Capability Structure Version 2.0 described
in Table 6–8 on page 6–4. For all other functions this field is
reserved and must be hardwired to 0x0000b. Four time value
ranges are defined:
Range A: 50 µs to 10 ms
■
Range B: 10 ms to 250 ms
■
Range C: 250 ms to 4 s
■
Range D: 4 s to 64 s
■
Bits are set to show timeout value ranges supported. 0x0000b
completion timeout programming is not supported and the
function must implement a timeout value in the range 50 s to
50 ms.
Chapter 3: Parameter Settings
Port Functions
Table 6–8 on
November 2011 Altera Corporation