Thursday, February 1, 2018

a Hardware Design for XOR gates using sequential logic in VHDL

Hybrid boards with ARM processors integrate FPGAs with multicore ARM processors over high speed buses.  The ARM processor is termed the hard processor system or HPS.  Writing to the FPGA from the ARM processor is typically performed via C from an embedded Linux build (yocto or buildroot) running on the ARM core.  A simple bitstream can also be loaded into the FPGA fabric without using any ARM design blocks or functionality in the ARM core.

ModelSim Wave Output for the xor design
The following is a simple hardware design that I wrote in VHDL and subsequently simulated in ModelSim.  The HPS is not used. The bitstream is loaded into the FPGA fabric on boot.  The sequential design is comprised of several XOR gates, XNOR'd together with a 50Mhz input clock. XOR gates are common in cryptography.  VHDL components are utilized and a testbench is defined for testing the design.  The testbench for the design was loaded into ModelSim and the below image is the wave form simulation of the input signals, clock, and output signal.

The source code is available on github at the following link.
xorchain hardware design in VHDL

ModelSim Full Window view with wave form output of xor simulation. ModelSim-Intel FPGA Starter Edition © Intel

Sunday, February 12, 2017

Setting up a D-Star Access Point on Raspbian with PIXEL - Part II

This is part II of a two Part series. In part I, DStarRepeater and IRCDDBGateway were compiled and DstarRepeater was configured on Raspbian Jessie with PIXEL.  In Part II, IRCDDBGateway will be configured,and an Icom ID-51a+ will connect to the D-Star network through the D-Star hotspot.

Elizabeth Tower at the North end of the Palace of Westminster in London


Requirements


Directions


Configure ircddbgateway


Execute ircddbgatewayconfig on the target (Raspberry Pi) as follows.


pi@hbox:~ $ sudo ircddbgatewayconfig &






Replace KF5SVQ with your call sign.


Make sure that you select Save from the File Menu in order to save your changed to the configuration file.   Also make sure that you select Exit from the File menu after you select Save.

Start ircddbgateway and dstarrepeater

pi@hbox:~ $ sudo ircddbgateway &
pi@hbox:~ $ sudo dstarrepeater &



Configure the Radio 


Link to the UK D-Star Megarepeater

D-Pad -> Repeater List -> Simplex -> 145.67 DV
Press PTT
D-Pad -> Local CQ
Hold Down PTT and Talk

Setting up a D-Star Access Point on Raspbian with PIXEL - Part I

This is part I of a two Part series. In part I, DStarRepeater and IRCDDBGateway will be compiled and DStarRepeater will be configured on Raspbian Jessie with PIXEL.  In Part II, IRCDDBGateway will be configured and an Icom ID-51a+ will connect to the D-Star network through the D-Star hotspot.

Purpose


Create a hotspot or access point for a handheld radio in order to connect to the D-Star network.




Requirements





Definitions


Host - Your Desktop computer (Linux)
Target - Raspberry Pi 3 running Raspbian Jessie with PIXEL (Linux)






Directions


Write the Raspbian image to the uSD on the host.  Execute the following commands on the host.

dev@fedora:~ $ sudo umount /dev/sdb*
dev@fedora:~ $ sudo dd if=2017-01-11-raspbian-jessie.img of=/dev/sdb bs=1M

Boot the Pi with the uSD card.  Execute the following commands on the Pi.

pi@hbox:~ $ apt-get install libwxgtk3.0-dev libusb-1.0-0-dev
pi@hbox:~ $ mkdir ~/src
pi@hbox:~ $ cd ~/src
pi@hbox:~ $ git clone https://github.com/dl5di/OpenDV.git -b master
pi@hbox:~ $ cd OpenDV/ircDDBGateway
pi@hbox:~ $ ./configure
pi@hbox:~ $ make
pi@hbox:~ $ sudo make install
pi@hbox:~ $ cd ..
pi@hbox:~ $ cd DStarRepeater
pi@hbox:~ $ ./configure
pi@hbox:~ $ make
pi@hbox:~ $ sudo make install
pi@hbox:~ $ sudo mkdir -p /usr/local/etc/opendv
pi@hbox:~ $ sudo mkdir -p /usr/local/var/log/opendv


Configure DStarRepeater


Execute dstarrepeaterconfig on the target as follows.
















Replace KF5SVQ with your call sign.