Xilinx CPLD Libraries Guide

FJKP
Macro: J-K Flip-Flop with Asynchronous Preset
Supported Architectures
This design element is supported in the following architectures only:
• XC9500XL
• CoolRunner XPLA3
• CoolRunner-II
Introduction
About Design Elements
This design element is a single J-K-type flip-flop with J, K, and asynchronous preset (PRE) inputs and data
output (Q). The asynchronous preset (PRE) input, when High, overrides all other inputs and sets the (Q) output
High. When (PRE) is Low, the (Q) output responds to the state of the J and K inputs, as shown in the following
logic table, during the Low-to-High clock transition.
For CPLD devices, this flip-flop is asynchronously cleared, output Low, when power is applied. You can simulate
power-on by applying a High-level pulse on the PRLD global net.
Logic Table
Inputs Outputs
PRE J K C Q
1 X X X 1
0 0 0 X No Change
0 0 1 › 0
0 1 0 › 1
0 1 1 › Toggle
Design Entry Method
This design element is only for use in schematics.
For More Information
• See the appropriate CPLD User Guide.
• See the appropriate CPLD Data Sheets.
CPLD Libraries Guide
374 www.xilinx.com ISE 10.1