I power down the converter after each failure to reset the device.
I am using a USB to serial cable from US converters (sx8801) to connect the controller to the PC and not a standard serial port
I have an oscilloscope but have not been able to see very well what is sent out the port.
The first linux command I sent was
echo -ne “\128\1\0\1\79” > /dev/ttyUSB0
which resulted in the red led on, green flashing indicating port was configured to fast.
I slowed the port down with the above commands and get yellow on, red flashing…
Immediately yellow on, green off, red flashing.
4)internet search, change multiple setting, try sending data single byte at a time, always resetting the controller by powering down and back up resulting in all LEDs on; get the same results.
5) abandon c++ program and try issuing linux commands
6) first issue ’ echo -ne “\128\1\0\1\79” > /dev/ttyUSB0’ results in green led lit, red flashing, yellow off.
7) slow the port down with ‘stty -F /dev/ttyUSB0 speed 9600’
’ echo -ne “\128\1\0\1\79” > /dev/ttyUSB0’
results in yellow on, green off, red flashing
8) issue commands
stty -F /dev/ttyUSB0 speed 9600
stty -F /dev/ttyUSB0 speed
stty -F /dev/ttyUSB0 cs8
stty -F /dev/ttyUSB0 -cstopb
stty -F /dev/ttyUSB0 -parenb
echo -ne “128” > /dev/ttyUSB0
results in yellow on, green off, red flashing.
9) am using a USB to serial converter( US converter model xs8801), not a standard serial port as this mother board does not have an output the back plane.
All LEDs on is not good for the starting point; it indicates your serial line is being held low (on the TTL side). It looks like your adapter is an RS-232-level adapter, so I am concerned you are applying the high voltages (relative to a microcontroller) to the logic-level input. Can you confirm that when you disconnect everything else and only apply power to the servo controller, you get just the yellow LED on?
You should also really get the oscilloscope going.
By the way, why are you using this old servo controller instead of the newer Maestros?
We have merged your two posts since they are about the same issue.
We tested echo -ne "\128\1\0\1\79" on a Linux computer and the format is invalid. We suggest you to send the commands in hexadecimal format \xNN, where NN represent a two digit hexadecimal value.
By the way, you might consider the newer Maestro USB Servo Controllers (that Jan mentioned), which are better in almost every way.
The micro serial servo controller can accept RS-232 signals, so it should work with your USB to serial adapter cable if it sends RS-232 signals. Are you connecting to the COM (RS-232) pins on the board?
By the way, did you try sending the command bytes and values in hexadecimal format? If you did, can you let us know the results?
The Maestro has a TTL serial interface that you can use if you only want to send serial commands. You can learn more about the Maestro’s serial interface under the “Serial Interface” section of the Maestro’s user’s guide. The Maestro can also be controlled from your computer via USB, and you can use our Pololu USB Software Development Kit to write your own software using more advance native USB commands for the Maestro. The SDK includes examples written in C#, Visual Basic .NET, and Visual C++, so you can get an idea of how to call its functions. Also, there are various customer-contributed examples for the Maestro that might be useful to you, which you can find in the “Related Resources” section of the Maestro’s user’s guide.
got rid of the XS8801 USB to serial cable and plugged in the serial port on the motherboard and all seems to work fine…Guess that cord is not compatible.
