Opencore: Quad 12bit DAC (LTC2624) in VHDL
Hello my readers, if I have any 
Summer is going on, my studies in FPGAs should also have an increase, but I had only a couple of days for vacation. Work work work! 
However I will keep my post short. This time I have implemented LTC2624 Quad 12bit DAC, which is placed on my Spartan-3E devkit, in VHDL. The module could be a bit tidier, but I think it is very easy to understand, plus I added some comments in the source. Read the rest of this entry »
Every fail is a lesson
Hello dear readers! Another one post with fail after success So I’ve managed to make SPI working on FPGA, but my first try using shift_left() did not work, so the solution is to use an array with counting array number, like array(i) and count incoming bytes after FF (not 0xFF, its FLIP-FLOP).
Ok back to my post. I’ve got 800×480 LED backlight LCD panel, which has 40 pins (yes, exact the same number as on my FX2 breakout board). However, I can’t remember LCD manufacturer. So they gave me some connectors and I had to solder it on breakout board. This is how I made it:
The wires I used was from very old HDD IDE 40 wires cable. Read the rest of this entry »
Altera BeMicro – expect nothing for small money
Hello again! Since I had to start forever loop on my ToDo task “Update blog”, here I am again! Ok, this entry will be about my new devboard, which I got from Arrow and its called Altera BeMicro. Here is how it looks like:
Looks really small heh? It has FTDI USB to 2xSerial chip, Cyclone III EP3C16F256 FPGA, ISSI SRAM, 8 LEDs, edge connector with 80 pins and an empty space for EPCS4 memory. Read the rest of this entry »
A little update
Hello my readers, long time – no talk . Work, studies and my lazyness lead to making this blog almost dead. Additionally, I have bought a new domain (www.scrts.net) and was thinking to revive this blog on the other server, but many blog fallowers asked me to update my blog as is. So thats it, I have made a major comeback!
Firstly, my bad, but my FPGA designs were slowed, but I am still trying to learn design in small steps, so here You can see my additional boards. 
I have bought a breakout board for FX2 connector, which was a waste of money since the FX2 connector has 100 pins, remove JTAG pins, additional clock, many pins are connected together with LEDS on the board or other devices, also its better not to connect Your LVTTL pins to differential IO pins, finally we have about 20 useful pins… Anyway, as seen in the photo I have made two additional boards by myself. The one on the left is a board with Atmel ATmega8L, which runs from 3.3V, connected to the FPGA for I2C and SPI tests. Read the rest of this entry »
Unlocking HTC T-Mobile Shadow or HTC JUNO and more
Posted by admin in Uncategorized on August 12, 2009
For most of my time surfing eBay, I am interested in mobile phones with crashed/broken screens. They are usually really cheap, so I buy a phone and a new screen also from eBay at the same time. Recently I got LG Shine KE970 that I repaired replacing the broken screen, then sold it and also got HTC Shadow 2007 version with totally non-working screen. I have searched eBay for screens, but almost all auctions offered screen for 35-36USD then, so I waited till I found a screen from China manufacturer for 14.5USD. Read the rest of this entry »
4-to-16 and 16-to-4 in one
Recent project had many problems due to long part searching and many dead ends. The main problem was 4-to-16 multiplexer and demultiplexer (actually I needed 4-to-9, because there are 9 devices), since 74HC154 is available, but SY100S364 is hard to get here and it does not support 3V3 levels, so I have decided to use Xilinx XC9572XL CPLD device in VQ44 package to make mux/demux device.
Read the rest of this entry »
Speed speed speed! Hacking USB Gadget serial driver
The latest task for me using ARM9 devboard was to try to start USB slave device in the board. Since I was using Linux kernel 2.6.29.1, I have searched for the solution for starting devboard as a slave device using USB and the solution was found using USB Gadget device as it offers USB device as ethernet device, serial device or mass storage device, so I have chosen using communication via serial port, because it is easy to read and write data and also there are Windows drivers for it.
Read the rest of this entry »
International Student Conference on Electrical Engineering
Posted by admin in Publications on April 3, 2009
Hello, first time in my life I have made publication to international conference . So my publication was about static probing distance meter with wireless communication. There is a book of the conference with all publications (Telecommunications and Electronics – 2009, Technologija, Kaunas 2009, ISBN 978-9955-25-655-7). Here is the abstract:
T. Daujotas. Statical probing distance meter with wireless communication.
Problems of distance measuring when statical probing is started. Many problems occour when statical probing begins and wires disturb the speed and quality of work, so using wireless communications helps to avoid these issues.
The whole publication in Lithuanian language will be publicated later.
Reading GPIO input in Linux
Since the GPIO can be as input, I have written a kernel module, which shows the status of the input. If the input is high, output of the device file will be 1 and 0 otherwise. Loaded module creates a misc device in /dev directory called gpiopb21, so if you read this file using cat, the output will be 1 or 0. As you can see, this software is used for PB21 pin reading. Source code can be found here.
Controlling GPIO pins in Linux
I had to reach GPIO pins to make AT91SAM9263 board useful, but it is not easy in Linux, because all hardware is controlled by kernel and commands from userspace can’t affect hardware, that’s why I had to write my own kernel module for GPIO control. The loaded module creates a misc device in /dev called gpio for PB8 pin control. The port can be controlled using echo. For example, echo 1 > /dev/gpio will set gpio pin PB8 to be high (5V output). The current version of the module is used for setting pin high or low. Here is the code: Atmel ARM9 Linux GPIO.