User guide

Chapter 7: IP Core Interfaces 7–25
Cyclone V Hard IP for PCI Express
December 2013 Altera Corporation Cyclone V Hard IP for PCI Express
User Guide
Reset Signals
Table 7–6 describes the reset signals.
Table 7–6. Reset and Link Training Signals (Part 1 of 3)
Signal I/O Description
npor I
Active low reset signal. It is the
OR of pin_perstn and the local_rstn signal coming from
software Application Layer. If you do not drive a soft reset signal from the Application Layer,
this signal must be derived from
pin_perstn. You cannot disable this signal.
reset_status O
Active high reset status signal. When asserted, this signal indicates that the Hard IP clock is
in reset. The
reset_status signal is synchronous to the pld_clk clock and is deasserted
only when the
npor is deasserted and the Hard IP for PCI Express is not in reset
(
reset_status_hip = 0). You should use reset_status to drive the reset of your
application.
nreset_status O
For the Hard IP for PCI Express IP Core using the Avalon-MM interface,
nreset_status is
an active low reset signal.
apps_rstn , which is derived from npor or pin_perstn drives
nreset_status.
pin_perstn I
Active low reset from the PCIe reset pin of the device. This reset signal is an input to the
embedded reset controller for PCI Express in Cyclone V devices. It resets the datapath and
control registers. This signal is required for CvP.
Although CvP is not supported in the current release, Altera is providing the following
information about the placement of the
pin_perstn pins to facilitate advanced layout of
PCBs. Cyclone V devices have 1 or 2 instances of the Hard IP for PCI Express. Each instance
has its own
pin_perstn signal.
Cyclone V devices have a
nPERST pin for each available instance of the Hard IP for PCI
Express. These pins have the following locations:
■ nPERSTL0 : Top left Hard IP
■ nPERSTL1 : Bottom left Hard IP and CvP blocks
For maximum use of the Cyclone V device, Altera recommends that you use the bottom left
Hard IP first. This is the only location that supports CvP over a PCIe link.
Refer to the appropriate Cyclone V device pinout for correct pin assignment for more
detailed information about these pins. The PCI Express Card Electromechanical Specification
2.0 specifies this pin to require 3.3 V. You can drive this 3.3V signal to the
pin_perst pin
even if the V
CCIO
of the bank is not 3.3V if the following 2 conditions are met:
■ The input signal meets the V
IH
and V
IL
specification for LVTTL.
■
■
The input signal meets the overshoot specification for 100C operation as specified by the
“Maximum Allowed Overshoot and Undershoot Voltage” section in the Device Datasheet
for Cyclone V Devices in volume 1 of the Cyclone Device Handbook.
Refer to Figure 7–29 on page 7–27 for a timing diagram illustrating the use of this signal.
serdes_pll_locked O
When asserted, indicates that the PLL that generates the
coreclkout_hip clock signal is
locked. In pipe simulation mode this signal is always asserted.
pld_core_ready I
When asserted, indicates that the Application Layer is ready for operation and is providing a
stable clock to the pld_clk input. If the coreclkout_hip Hard IP output clock is sourcing
the
pld_clk Hard IP input, this input can be connected to the serdes_pll_locked output.