Zynq-7000 AP SoC and 7 Series FPGAs MIS v4.1
293
UG586 November 30, 2016
Chapter 2:
QDR II+ Memory Interface Solution
•
Reference Clock
– This option selects the clock type (Single-Ended, Differential, No
Buffer, or Use System Clock) for the
clk_ref
signal pair. The
Use System Clock
option
appears when the input frequency is between 199 and 200 MHz (that is, the Input Clock
Period is between 5,025 ps (199 MHz) and 4,975 ps (201 MHz). When the
No Buffer
option is selected, IBUF primitives are not instantiated in RTL code and pins are not
allocated for the reference clock.
If the designs generated from MIG tool for the
No Buffer
option are implemented
without performing changes, designs can fail in implementation due to IBUFs not
instantiated for the
ref_clk_i
signal. So for
No Buffer
scenarios,
ref_clk_i
signal
needs to be connected to an internal clock.
•
System Reset Polarity
– The polarity for system reset (
sys_rst
) can be selected. If the
option is selected as active-Low, the parameter
RST_ACT_LOW
is set to 1 and if set to
active-High the parameter
RST_ACT_LOW
is set to 0.
•
Debug Signals Control
– Selecting this option enables calibration status and user port
signals to be port mapped to the ILA and VIO in the
example_top
module. This helps
in monitoring traffic on the user interface port with the Vivado Design Suite debug
feature. Deselecting the
Debug Signals Control
option leaves the debug signals
unconnected in the
example_top
module and no ILA/VIO modules are generated by
the IP catalog. Additionally, the debug port is always disabled for functional
simulations.
•
Sample Data Depth
– This option selects the Sample Data depth for the ILA module
used in the Vivado debug logic. This option can be selected when the
Debug Signals
for Memory Controller
option is ON.
•
Internal V
REF
Selection
– Internal V
REF
can be used for data group bytes to allow the
use of the V
REF
pins for normal I/O usage. Internal V
REF
should only be used for data
rates of 800 Mb/s or below.
Click
Next
to display the
Extended FPGA Options
page.