[Ncartmell]

Hello,

I have just found your site and the project looks very interesting.

Have you frozen your design?

The reason I ask is that I am member of MERG and they design electronics for model
 railways and they made a USB module using an FTI USB interface.

These interfaces are expensive so they removed the FTI USB interface and replaced it with a PIC, the price of the USB module kit then fell dramatically from £20+ to just £9, all down to the price of the FTI USB interface.

If you are interested I can ask if you can use there code/design they are also open source.

Best Regards

Neil

[LukeZ]

Hi Neil, welcome to the forum. Our board is too close to production for any hardware changes at this point, and even seemingly small changes do require a great deal of time to fully implement, so the hardware is definitely fixed for this generation. However if this one is successful there could be a Mk II someday, but not for several years.

All the same I'd be interested to hear what chip your group went with. If it is the MCP2220/MCP2221 then I did consider those, one thing they did not have is the ability to pass the DTR signal. This is not needed for pure USB communications but the Arduino environment is unique in that it uses DTR to reset the device for flashing.

But you are right the PICs are certainly less expensive and that is one of the drawbacks of the FTDI. On our board the FTDI is the 3rd most expensive component, after the processor and the L298 dual motor driver.

[Ncartmell]

Hello Luke,

The designer has said yes to using/adapting his circuit/software.

The only difference is that this design is a parallel output, but it could give ideas or you could modify the circuit.

It of course may be of no use whatsoever.

They have produced a Technical Bulletin detailing it.

How do I send you a pdf?

Neil

[LukeZ]

You can attach a PDF to any post, see the "Attachments and other options" section when you submit a reply. But of course then it will be visible also to the public.

Otherwise you can email it to me, I will send you a PM with my address.

[LukeZ]

Neil, I received your attachment. The original FTDI chip your group used was a FT245R, which is not a USB-to-serial converter, it was a USB to parallel interface. The chip they replaced it with (PIC 18F14K50) served the same purpose.

What we need on the TCB and what almost all USB-enabled microcontroller devices today use, is a USB to serial device. So yeah, the two are completely different and this wouldn't be of use in our application even if we were still in the hardware design stage.

Thanks for the thought though!