Cannot use RFU with FT231XQ, on a board with RCM6700

Rabbit
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1

Hello,

Last years we have used RCM6700 successfully in couple of our projects.
Now we have two new projects in which we will use RCM6700.
But the first samples of the two boards have problems uploading firmware through the programming port.
The difference between the new and the old boards is the USB chip.
The new boards are using FT231XQ, and the old - FT232RL.
We have tried to program RCM6700 with all speeds and options from the RFU interface, but without success.
With DC 10.70 it is possible to program RCM6700, but only when “Max Download Baud Rate” is set to 57600.
The last means that the wiring is OK, but there is some strange problem that we cannot fix.
Also the debugging is not possible at all baud rates, even at 2400 bps.

We have performed independent additional testing of the FT231XQ performance at different speeds, it looks OK.
The timing and fronts also look OK on the oscilloscope, like those using FT232RL.

Can you help us to determine where is our problem with the programming / debugging of the RCM6700?
I can save some screenshots from the oscilloscope and send them to you, if it will help you to discover the problem.

Best regards,
Alexander Hristov,
TeCoSys

2

According to the schematic and the bill of materials, the RCM6700 interface board is still using FT232RL.

Where did you get different information?

3

Are you using the Digi interface board? Or is this your design?

4

We use Digi’s core modules in our products, but make our designs for the rest part of the devices.
We use different FTDI USB chips on our boards for USB2 connections.

The differences that we have found on the new boards are:

  • FT231XQ changes the baudrate faster;
  • Rabbit Tx stays low, as staying in a break condition.
5

Dynamic C does not support FT231XQ. If you wish to use this chip in your design, you should contact sales for a feature request.

6

Dynamic C does not support FT231XQ. If you wish to use this chip in your design, you should contact sales for a feature request.