Achronix Speedster22i User Macro Guide - Manual (Page 65)

Speedster22i Macro Cell Library Achronix Semiconductor Proprietary PAGE 49
Chapter 2 – Registers
Naming Convention
These Macros are named based upon their characteristics and behavior. In each case, the name
begins with DFF for D‐type Flip Flop. In addition to DFF each has one or more modifiers
which indicates it’s unique properties.
The modifiers are:
E ‐ Enable
N ‐ Negatively Clocked
R ‐ Reset (has priority over enable)
S ‐ Set (has priority over enable)
C ‐ Clear (enable has priority)
P ‐ Preset (enable has priority)
DFF
Positive Clock Edge D-Type Register
d
ck
DFF
q
Figure 2-1: Logic Symbol
DFF is a single D‐type register with data input (d) and clock (ck) inputs and data (q) output.
The data output is set to the value on the data input upon the next rising edge of the clock.
Pins
Table 2-1: Pin Descriptions
Name Type Description
d Data input.
ck Positive-edge clock input.
q
Data output. The value present on the data input is transferred to the q out-
put upon the rising edge of the clock.
input
input
output