Author Topic: FTDI FT231 FT232 drivers  (Read 12666 times)

Felix

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Re: FTDI FT231 FT232 drivers
« Reply #15 on: December 26, 2014, 11:27:15 AM »
Last 3 weeks I searched for my problems with Moteino-USB too. I tested a lot of drivers and had to reboot my PC (W7, 64 bit) for 100 times. But I didn't found the bug.
So I tested all my USB cabels I found here. The short cables (max. 1 ft) are working, but the longer cables (2 - 6 ft) didn't work.
So I studied the datasheet of the FT232RL and the FT231X. I found the difference: The FT231X must have 2 resistors (27R) in the USB data lines (to match the USB line impedance of 90 Ohm) and the RESET# have to be connected to 3V3OUT.
I cutted the datalines and soldered the 2 resistors in the lines (I only found some 1206 resitors).
For the RESET# connection I make a small solder bridge between pin 13 - 14 of FT231X.
Now my 2 Moteinos are working fine :-))

Merry Christmas from Germany
Wilfried


Wilfried,
This is the consensus after some research and information from other sources as well. It looks like depending on static and other conditions like noise on longer cables, the resistors will make the difference. The datasheet contains the resistors but never mentions they are required or why they are 27ohm. Any future design revisions of all FT231xs chips will include these changes. Thanks for adding in your findings.
Merry Christmas!

HeneryH

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Re: FTDI FT231 FT232 drivers
« Reply #16 on: December 27, 2014, 10:26:03 AM »
...
The FT231X must have 2 resistors (27R) in the USB data lines (to match the USB line impedance of 90 Ohm) and the RESET# have to be connected to 3V3OUT...
The solder bridge for reset~ seems pretty easy since pin 14 (reset~) is right next to 13 pins (3.3) and 15 (vcc) .  The resistors in-line are much more challenging for me at my skill level.  Did you happen to try one fix without the other to see of you get any benefit from just pulling up the reset~ line?
« Last Edit: December 27, 2014, 10:33:07 AM by HeneryH »

Felix

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Re: FTDI FT231 FT232 drivers
« Reply #17 on: December 27, 2014, 09:53:01 PM »
If you follow the D+/D- lines they go through vias over the other side where you could cut the traces and scrape them to allow soldering a 0603 resistor on each trace. This is tedious but if you do it once it gets easy.

DD9FL

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Re: FTDI FT231 FT232 drivers
« Reply #18 on: January 05, 2015, 04:16:16 PM »
Here are the photos of my modified Moteino.
The 2 resistors (27R, 0603) are feed into the D- and D+ USB lines.
At the 2nd photo you will find the bridge between Pin 13 an 14 of the FT231X (Reset pin).
I don't checked the reset pin with and without the bridge.

The resistors are necessary because of the low impedance (~36 Ohm) of the FT231X input/output at the USB pins.
The ímpedance of an USB cable is 90 Ohm. If you will terminate the cable with 36 Ohm there will be a lot of reflections.
If you terminate the cable with 90 Ohm (27R + 36R + 27R) there are no reflections and the data transmission will be ok.
If you short the resistors and you use a very short USB cable, the echos are to short in relation to the transfer rate (12 Mbit/s @ USB 2.0). When you use a longer cable or an expensive lossless cable you will expect data transmission problems.

Wilfried

Felix

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Re: FTDI FT231 FT232 drivers
« Reply #19 on: January 28, 2015, 01:47:09 PM »
Heads up - MoteinoUSB and FTDI adapters are now shipping with the D+/- resistors and FT231 RST pullup. I will post photos of them soon on the product pages.

CapnBry

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Re: FTDI FT231 FT232 drivers
« Reply #20 on: June 06, 2015, 09:31:02 AM »
Here are the photos of my modified Moteino.
The 2 resistors (27R, 0603) are feed into the D- and D+ USB lines.
At the 2nd photo you will find the bridge between Pin 13 an 14 of the FT231X (Reset pin).
Wilfried, you are my hero. I use a Moteino to receive the power meter readings from an Black and Decker EM100B PowerCost 433Mhz transmitter that is outside. The signal strength at my "base station" is pretty weak, leading to me needing to have an antenna stuck to my wall to get any sort of reliable signal. I had tried endlessly to run the moteino on a Raspberry Pi 2 Model B in another room closer to the transmitter and the FTDI USB driver would error out within 30 seconds claiming a USB bus error.

I've modded my moteino with your 27 ohm resistor fix and it has been working brilliantly for a day now. I assume the combination of the signal reflections and the Pi's garbage USB controller were just too much for the driver to deal with. Thank you so much for sharing your fix!


rpetz2007

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Re: FTDI FT231 FT232 drivers
« Reply #21 on: June 15, 2015, 10:43:31 AM »
You guys rock - I was banging my head against a wall trying to get my USB moteino to come up as a proper device in Windows.  After moving to a short USB cable they register correctly

Thanks guys

HeneryH

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Re: FTDI FT231 FT232 drivers
« Reply #22 on: August 05, 2015, 02:06:09 PM »
I don't see renderings of the MotionMot on GitHub so I had to post pictures which aren't that great.  I don't have a macro lens.

Any suggestions for cutting traces and soldering in the resistors on the MotionMot?  I'm guessing it would be on the top view between the connector and that chip.  That could be very difficult to mod.  I only have a single FTDI adapter and that just got used by my Pi-Gateway master.  Now I need to fix my MotionMots or USBMot to get running again.





Here is a better image from Felix's web site


Hmm, images aren't showing up.  Hold please...  Frickin google photos has always been a PITA for sharing photos via link. 
« Last Edit: August 05, 2015, 02:51:13 PM by HeneryH »

Felix

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Re: FTDI FT231 FT232 drivers
« Reply #23 on: August 05, 2015, 10:19:08 PM »
HeneryH,
Unfortunately the traces are short and they don't transition on the bottom. If you're very good, you could cut the traces in the middle, scrape the mask off and solder the resistors in line. 0603 will be tight, 0402 might work well but difficult to handle due to the small size.
May I suggest trying a very short shielded cable and that might solve all your issues.

Anywsay here's what they look like in R2, notice the 0603 27ohm resistors:



I've just done an exercise on a SonarMote which also had the same issue and it works ok, a bit tedious to get a very fine soldering tip in there but it works.
You have to first scrape the mask, but don't scrape it off anywhere but from the traces otherwise you risk making bridges when soldering, then cut 1/3 of the length of those traces in between the chip and the USB, then wet them with flux/solder, then wet flux resistors, then carefully solder each resistor. Results below. The D- trace is close to the VCC/5V from the USB so avoid making a bridge there.
« Last Edit: August 05, 2015, 11:24:17 PM by Felix »