Why can’t I access COM Ports above COM9 on Windows?

Serial ports were used in a verity of applications reliably for a very long time now. Although PCs and Laptops don’t come with built in serial ports anymore, serial port interface emulated over USB is very popular among DIYers/hackers and with certain products. USB specification defines a class (Communication Devices Class) for using USB transport and infrastructure to emulate serial port interface thus legacy applications can continue operate even when the hardware uses USB. This also allows for a range of products such as Numato Lab’s USB GPIO and USB Relay modules to use USB but still have the ease of use Serial interface offers. An example of such a device is in the image below as shown in Windows Device Manager.

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Creating Xilinx EDK test project for Saturn – Your first Microblaze processor based embedded design



The most exciting thing about FPGAs is their ability to process problems in parallel manner. This gives FPGAs clear advantage over microprocessors. But when it comes to implementing sequential algorithms, FPGAs may not be the best option due to increased complexity. The “best of both worlds” option would be to implement sequential algorithms on a microprocessor and custom logic that requires parallelism on FPGA fabric. There are three ways to accomplish this.

  1. Include a Microprocessor/Microcontroller and FPGA on your board and establish a mechanism for communication between these these two elements
  2. Use a FPGA with built in embedded processor such as ARM/PPC
  3. Build a soft processor within FPGA fabric

All these options has its own advantages and disadvantages. Option 1 will give

Saturn, Microblaze and Linux – How to Run Linux on Saturn Spartan 6 FPGA Module – Part II


In Part I, we saw how to generate a microblaze based minimal embedded hardware platform for Saturn Spartan 6 FPGA module. Now we recommend that you create a SDK application project for this hardware platform and test it’s basic functionality by creating a “Hello world” application. Please follow the steps under the section “Creating Application program for Microblaze based Embedded Platform” in the article Creating Xilinx EDK test project for Saturn – Your first Microblaze processor based embedded design to create a SDK project. Choose “Hello world” SDK application template when generating the application. Run the application on the board to make sure that everything so far

Saturn, Microblaze and Linux – How to Run Linux on Saturn Spartan 6 FPGA Module – Part I



Though a low cost FPGA board, Saturn Spartan 6 FPGA Module is perfectly capable of running Linux with Xilinx’s popular Microblaze 32 bit soft processor. Recently we spent some time trying to figure out how to build Linux for Saturn. Surprisingly (or not!) it turned out to be fairly easy to do. Building the Linux Kernel was very easy, but creating a bootloader to boot Linux off of the on board SPI flash was a little more involved. We are excited to share what we learned with our readers. Though this article series is mainly focused on building Linux for Saturn a Xilinx

Configuring FT2232H USB Serial converter on Saturn Spartan 6 Module

Saturn Spartan 6 FPGA module has an onboard FT2232H USB to serial device for easy communication with the host. FT2232H has two channels and are usually called Channel A and Channel B. These channels are separate USB multiprotocol engines which can independently act as separate serial ports or other protocol converters. Besides RS232 style serial interface, FT2232H supports I2C, SPI, JTAG etc..

Channel A of the FT2232H on Saturn Spartan 6 FPGA Module is dedicated for SPI flash programming. This way, your design can be downloaded to the board without using a dedicated JTAG cable. Since the design is written directly to the on board SPI flash, it will stay persistent even after a power cycle. The configuration tool does not support programming FPGA SRAM directly at this time.

Channel B

Saturn, Microblaze and Linux – How to Run Linux on Saturn Spartan 6 FPGA Module – Part III


In Part I and II of this article series, we saw how to create a Microblaze based embedded platform for Saturn Spartan 6 Module and build Linux kernel for it. In this tutorial we will take a look at how to download the kernel image to Saturn and boot using Xilinx Platform cable USB and XMD (Xilinx Microprocessor Debugger).  Xilinx Platform cable USB slightly expensive, but if you don’t have one don’t loose hope. There is still a way to download the kernel and boot. This is discussed in Part IV of this article series.

Before we continue, we need to make sure that the channel B of

Saturn, Microblaze and Linux – How to Run Linux on Saturn Spartan 6 FPGA Module – Part IV


In previous articles in this series, we saw how to create a Microblaze based embedded platform for Saturn Spartan 6 FPGA module, how to build Linux kernel and boot Linux on Saturn using Xilinx Platform cable USB and XMD. Though this is the easier method, there are a couple of drawbacks associated to it. You will need a Xilinx Platform Cable USB which is slightly expensive and the images are programmed SRAM/DDR instead of SPI flash. It is possible to program the onboard SPI flash with the images which would retain contents even after power cycle and this can be done without buying expensive JTAG cables.

Before we

Saturn – Another Attempt To Make Open Source Spartan 6 FPGA Board with DDR SDRAM


Some readers may remember, we attempted to design a Spartan 6 based FPGA development board with DDR SDRAM almost a year ago. The board worked to the most part except that some obvious mistakes made it impossible to get the DDR up running. We did another attempt this year to design a new board with similar Spartan 6 FPGA and LPDDR. Of course adhering to the same primary principles, 100% open source and 100% KiCad design. I can tell you with great happiness that we have succeeded to make the design working and make it available for sale at our online store. This design is completely open source and designed using KiCad and other open source

DDR Spartan6 and DDR SDRAM Memory – Your First DDR Interfacing Project



Designing and building a FPGA development board that has two BGA devices was challenging enough. But what came next did seem equally challenging to us in the beginning. That challenge was testing the functionality of DDR interface. We had no prior experience of successfully  building a board with a DDR device. And those who know about DDR interface can tell that it is not very easy implementing. Thanks to the memory controller built in to Spartan 6 FPGAs and Xilinx MIG tool which helped us generate sample code. Searching through websites we found out that there are not many tutorials and good example projects that are easy to follow. And we thought we should share with our readers