June 2012
Altera Corporation
Stratix V Hard IP for PCI Express
8. Reset and Clocks
This chapter covers the functional aspects of the reset and clock circuitry for the
Stratix V Hard IP for PCI Express. It includes the following sections:
■
■
For descriptions of the available reset and clock
signals
Reset
Stratix V includes two types of embedded reset controllers. One reset controller is
implemented in soft logic. A second reset controller is implemented in hard logic.
Software selects the appropriate reset controller depending on the configuration you
specify. Both reset controllers reset the Stratix V Hard IP for PCI Express IP Core and
provide sample reset logic in the example design.
provides a
simplified view of the logic that implements both reset controllers.
Table 8–1
summarizes their functionality.
1
Contact Altera if you want to switch between the hard and soft reset controller.
1
Your Application Layer could instantiate a module similar to
altpcie_rs_hip.v
as
shown in
to generate
app_rstn
which resets the Application
Layer logic.
Table 8–1. Use of Hard and Soft Reset Controllers
Reset Controller Used
Description
Hard Reset Controller
pin_perst
from the input pin of the FPGA resets the Hard IP for PCI
Express IP Core.
app_rstn
which resets the Application Layer logic
is derived from
reset_status
and
pld_clk_inuse
, which are
outputs of the core. This reset controller is used for Gen1 ES devices
and Gen 1 and Gen2 production devices.
Soft Reset Controller
Either
pin_perst
from the input pin of the FPGA or
npor
which is
derived from
pin_perst
or
local_rstn
can reset the Hard IP for
PCI Express IP Core. Application Layer logic generates the optional
local_rstn
signal.
app_rstn
which resets the Application Layer
logic is derived from
npor
. This reset controller is used for Gen2 ES
devices and both Gen3 ES and production devices.
June 2012
<edit Part Number variable in chapter>