The InterSceptre is almost ready!

It has been a busy period the last few weeks and I did not have the time to update this blog. Although it is still a rather busy time, I decided to write something anyway because I started working on the prototype of the InterSceptre.


Click for a better view. Notice the valid data on the LCD.

I received the PCB and the parts last Tuesday and I assembled the board. Even though the board is not very complicated, there are a lot of things to test. The first tests are promising. The power supply is fine and the board runs from 3V3 or 5V. There are three different 5V entry points (2x USB & one external power supply) and switch over between these inputs works without resetting the Sceptre board (or the PC).

Also working is the I2C port with discrete level shifter. It is discrete because I tried to avoid SMD parts on this board and through-hole integrated level shifters are hard to find. To test it I use the Pocket Terminal which is part of Elektor project 080253 Running-in bench. This terminal is supposed to run from 5V, but the Sceptre runs from 3V3, so I2C communication is incompatible. The level shifter fixes this and the fact that I can write to the terminal and read its keys means that all is working fine.

The four multiplexed DAC outputs are working, which is cool. I can control them with the rotary encoder on the terminal.

Not tested yet are the RS232 & RS485/DMX512 ports, the MIDI interface, the JTAG port, the SPI port and the digital I/O. The SPI port is particularly interesting as the board has space for a WIZnet WIZ812MJ internet module (not mounted for the photo, it should go next to the power connector). The digital I/O is hanging from the I2C bus and some direct from the processor. This is also true for the ADC inputs, so I suppose they will work.

As you can see from the photo, the InterSceptre was designed to fit a standard box from Teko. I did this because this way you can use the Sceptre-InterSceptre combination as a nice stand-alone device. You could only mount the interfaces you need and away you go.

Worldwide Serial Web

You may have heard of WIZnet, the Korean company that makes several embedded Ethernet controllers with an integrated hardwired TCP/IP stack. Their flagship, the W7100, also has an 8051 compatible processor inside. They not only make & sell chips, they also sell modules, evaluation boards and even complete products that use their chips. These modules allow you to add Ether- & Internet connectivity to your project without much headache. WIZnet now also offers a great free (you have to register to get a serial number) software tool that lets you connect to serial ports over a network.

This tool called WIZ VSP (for Virtual Serial Port) is pretty cool indeed. It lets you install up to 99 real or virtual COM ports (the documentation talks about 255, but the software doesn’t let you go higher then COM99), as a server, a client or a shared port. A server will wait for clients to connect to it. A client connects to a server. The shared port uses UDP instead of TCP and will talk to one remote host and listen on a port.

A server supports multiple clients. This means that you can distribute data received on the server COM port to multiple clients that can all talk to the server. Such a configuration can be useful as a serial port concentrator, for instance.

The shared port over UDP can do the same thing as a server, except that it is connectionless. It also only talks to one other host (but listens to anyone talking to him), unless you specify a broadcast address.

I’ve tried the tool and it works remarkably well. The documentation is a bit cryptic at some points and the fact that I used one PC under Windows Vista complicated matters a bit, but in the end I managed to transmit serial data between two PCs in al three configurations. Here is how to do it:

First download the software and the manual (separate download!) and install the program. Then request a serial number by sending an email to the indicated address. When you get the serial (you may have to answer some questions) enter it when the program asks for it (without serial it will NOT work). Now you can start creating serial servers and clients.

On the “Create Connection” tab select the type of connection and the number of the serial port. Note that if the serial port exists in hardware, i.e. is real (can be a USB type or Bluetooth) you can clear the checkbox “Create as virtual serial port”. This way the software will use the real port and you can specify the serial port parameters (baudrate, data bits, etc.) on the “Connection prefs” tab. Depending on the connection type you will have to specify a host IP and a port number. You can configure some more on the other tabs and once you’re done, click the “Create connection” button. If the port did not yet exist you will now hear the typical Windows add-new-hardware sound and the port shows up in the tree display. To edit a created port you have to use the “Edit connection” tab.


This shows the server setup on a Vista PC.

On another PC you do the same thing, but complementary. If you created a server on the first, create a client on the second. If you created a UDP connection on the first PC, you should create also a UDP connection on the second. Make sure to specify the right host IP numbers and to use the same port numbers on both PCs. Also better switch of any firewalls. I had to do that on the Vista PC before my XP PC would receive any data even though Vista did receive without any problem.

BTW, as host IP it is also possible to specify “localhost”. This way you can make serial ports on the same PC talk to each other.


Here is the XP client that talks to the Vista PC.

To familiarize yourself with the tool I suggest to first only use virtual ports and a terminal program. This way you can type and see what happens.

Once you know how to properly setup WIZ VSP, your application can use a serial port on another PC, anywhere in the world! Or a serial device (f.i. a GPS) can transmit data to multiple hosts. I am sure you can come up with some other useful configuration. This is a very powerful tool and anyone using serial ports should get a copy of it. Now!

Oh, one more thing. Once the connections are established you can close the program without killing them.