View Full Version : Programming multiple Propeller USB protoboards in a finished project.

11-25-2010, 05:07 PM
I have a project that currently uses a Propeller USB Protoboard as the main controller but want to add 2nd Propeller USB board as a co-processor. At the moment I have a short USB extension cable from the main Propeller board to to side panel for programming. I'd like to install a USB hub inside the case (and leave it there) so that both USB Protoboards can be left connected to the hub and I can then just plug a single USB cable into the port on the outside to program either board. If it works I can easily hit any more Propeller boards if I need extra's.

Has anyone else added a USB hub in a project to allow for programming multiple Propellers from a single USB cable?


11-25-2010, 06:31 PM
Hi, good question, Yes there are several threads on connecting multiple propellers to multiple instances of the SPIN IDE. I have quoted one from Jan 2009 that I know of as I had this issue as well. I currently use multiple hubs/monitor-hubs etc.. to connect 2 or more propellers to a single machine. The issue is not the hub as USB is serial and agnostic about the connection - and we are not powering from USB - the issue is associating the right IDE with the right comm port by connecting and/or powering up the prop usb boards in sequence.
Essentially you connect/power up one of the props, associate with the IDE, then disconnet/power-off it, then connect/power-up the 2nd prop usb and associate (F7) the 2nd prop tool IDE, then reconnect/power-up the first. You will now be able to program both propellers at the same time from 2 different prop tools. Of course any C++/C#/VBasic/Java program that performs comms is separate from this and will not be affected as I also can run a java process communicating to a display board in my cubicle unaffected by the spin tool (total 3 FTDI comm ports in use).


thank you
/Michael O'Brien

11-25-2010, 06:41 PM
There is also a dual serial port version of the FT232, the FT2232

and even a four port FT4232 in case you need it!


11-25-2010, 08:15 PM
Perfect! I'm using the Parallax Propeller Protoboards that already have an on board USB chip. If I was laying out a new board I'd definitely think about the versions of the FTDI chip that support multiple COM ports but for now just using a hub should work. Each of the boards already appears as a unique COM port. I've just never tried using a USB hub yet and leave them connected to the hub. It will make the cabling a lot cleaner as I already have a female USB connector mounted on the case.


11-26-2010, 03:21 PM
The USB programming technique is also working with seven BASIC Stamps in the Tiny Stamp Supercomputer TSS. (http://forums.parallax.com/showthread.php?t=126245)

The Stamp IDE shows 7 com ports being used to address each stamp (see photo).

This runs off a BELKIN USB HUB which supplies the extra power needed to drive all the stamps at the same time.