Achronix Speedster22i User Macro Guide - Manual (Page 39)

I/O Cells IPAD_DIFFD
Speedster Macro Cell Library www.achronix.com PAGE 22
IPAD_DIFFD
Registered Differential Input Pad with Asynchronous or Synchronous
Set/Reset
q
ce
d
rstn
dout
pad
clk
data_en
rstn
IPAD_DIFFD
padn
Figure 1-11: IPAD_DIFFD Logic Symbol
IPAD_DIFFD is a registered differential input pad. Driving rstn low performs either a
synchronous or asynchronous reset of the input register as determined by the value of the
rstmode parameter. Upon assertion of the rstn signal, the input register is initialized to the
value determined by the rstvalue parameter.
Table 1-25: Ports
Name Type Description
pad Device pad.
padn
Comlement device pad. The padn input must be driven with the logical
complement of the pad input.
rstn
Reset input. The active-low rstn input performs either a synchronous or
asynchronous set/reset operation as determined by the rstmode parame-
ter. The value that is initialized into the register is determined by the value
of the rstvalue parameter.
data_en
Input Register Clock Enable. A high value on data_en enables the Input
Register to clock the value on pad into the Input Register at the next rising
edge of clk. A low value on data_en allows the Input Register to retain its
current value.
dout
Positive-edge based data output. Data is clocked from the differential
pad to dout on the rising edge of clk.
clk Clock.
Table 1-26: Parameters
Parameter Defined Values Default Value
locationp
locationn
iostandard “LVDS”
rstmode
rstvalue
pvt_comp “none”, “own” “none”
odt “off”, “on” “off”
termination “50”, “60”, “75”, “100”, “120”, “240” “50”
input
input
input
input
output
input
“” ““
“” ““
See Table 1‐2
“sync”, “async” “async”
“low”, “high” “low”