Fw: [UDB-dev] Re: FDTI USB Serial breakout board problem

[John McClelland]

 

----- Original Message -----

From: John McClelland

To: Adam Barrow

Cc: John McClelland

Sent: Sunday, February 06, 2011 4:49 PM

Subject: Re: [UDB-dev] Re: FDTI USB Serial breakout board problem

Just wanted to close this out...

 

I added an inverter to the sonar output and hooked up to the RX of the serial port, Vcc, GND and TX from sonar are the 3 wire connection.

 

Hooked FTDI with 3 wire, Vcc, GND and RX from FTDI with RX going to TX of port. 

 

This configuration has no floating pins on the serial port.

 

Still using old MP serialIO code (not updated to Bill's patch.

 

All works fine now.  From this I conclude it was a floating pin issue on the seriral port.  No pullup needed on TX of FTDI.

 

Just FYI, I tried the sonar detector on various reflective surfaces (textured carpet, towels, wicker, irregular plastic) and all returned good data.  I don't think we will have an issue with different surfaces as we use this for hover altitude control on the Quad (and eventually heli).  Open loop tests of the sonar and altitude control code looks good.  Flight tests hopefully in a day or two.

 

Thanks for all the assistance.

 

John

----- Original Message -----

From: Adam Barrow

To: uavdevb...@googlegroups.com

Cc: <uavdevb...@googlegroups.com> ; John McClelland

Sent: Saturday, February 05, 2011 3:53 PM

Subject: Re: [UDB-dev] Re: FDTI USB Serial breakout board problem

John,

 I realize that you already have the patch Bill is referring to, but wanted to point out that it may be the same issue. When we were developing is patch, I tried numerous times to reproduce the error on my UDBs with a three wire connection but wasn't able to. We decide that it was a combination of the open pin and enough EMI to generate noise on the pin. I would imagine that Jerry, like me, is just not triggering the condition rather than being immune to it.

Good luck integrating the sonar with the UDB, I'm hopefully going to be able to start working on my own integration here next week.

Regards,

Adam Barrow

On Feb 4, 2011, at 6:38 PM, "John McClelland" <mcclell...@gmail.com> wrote:

Thanks Bill

 

When you say "the code", you are talking about MatrixPilot FW?   Jerry and I are using the same Quad FW and he is able to make the 3 wire connection to FTDI work, but has a newer  version of the FTDI.   Were you suggesting there is new FW for the FTDI?

 

Best,

John

----- Original Message -----

From: William Premerlani

To: uavdevb...@googlegroups.com

Sent: Friday, February 04, 2011 5:02 PM

Subject: Re: [UDB-dev] Re: FDTI USB Serial breakout board problem

Hi John,

There was a bug in the older versions of the code that required a 4 wire connection between the UDB and an external serial port such as OpenLog or FTDI. If you used a 3 wire connection, noise on the unconnected pin would cause problems in the communications. The problem was eventually fixed so that you could use a 3 wire connection, I am not sure what version that was.

Bill

On Fri, Feb 4, 2011 at 6:51 PM, John McClelland <mcclell...@gmail.com> wrote:

Thanks Paul

The problem was when I removed the Tx line on the FTDI....does that also need to be pulled up?  The Rx line on the FTDI is hooked to the serial Tx.

John
----- Original Message ----- From: "Paul G." <relbo...@hotmail.com>
To: "uavdevboard-dev" <uavdevb...@googlegroups.com>
Sent: Friday, February 04, 2011 4:09 PM
Subject: [UDB-dev] Re: FDTI USB Serial breakout board problem

FTDI's need the input line pulled up or it may think its getting
characters all the time.

On Feb 3, 5:27 pm, "John McClelland" <mcclelland.j...@gmail.com>
wrote:

Maybe someone on can help with a problem I am having. Jerry and I are developing a sonar/baro altitude control routine for our Quads. Interfacing the sonar is through serial, analogue, or PWM. Our configuration requires serial, at least for development. We will go another route long term. This means we need to use the Rx on the serial port for the sonar at the same time we use the Tx to grab data for debugging into the PC through the FDTI serial/USB board. Jerry was able to make this work with a later version of the breakout board. Mine is behaving badly.

I have this FTDI USB/serial board:

http://www.sparkfun.com/products/718

This is the one the wiki tells how to hook up:

http://code.google.com/p/gentlenav/wiki/SerialConnection

I have the jumper open (removed solder blob)

I am supplying power to the UDB thru a servo cable (5V). Vcc on the serial port reads 4.97V.

I hook up GND from the serial port to GND on the FTDI, Tx from the serial to Rx on the FTDI, and serial Vcc to VccIO on the FTDI.

Buad on serial and COM port set to 9600

Only if I connect the Rx from the serial to Tx on FTDI do I get good data out. If I remove the serial Rx connection I get jibberish. But of course I need the Rx for the sonar.

Does the Rx line on the FTDI need to be grounded or pulled up?

Any idea what I am doing wrong?

John