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Serial communication through gumstix

Bioloid robot kit from Korean company Robotis; CM5 controller block, AX12 servos..
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7 postsPage 1 of 1

Serial communication through gumstix

Post by NEVER » Mon Nov 23, 2009 5:48 pm

Post by NEVER
Mon Nov 23, 2009 5:48 pm

I am sending data packets through the gumstix serial port(using a c program) to an rx64 motor.
When i send a data '0a'(in hex) the data received at the other end is actually 0d 0a (checked by a USBDynamixel).
Also, i am using a max485 chip to convert rx/tx data to rs485 standard.
I am sending data packets through the gumstix serial port(using a c program) to an rx64 motor.
When i send a data '0a'(in hex) the data received at the other end is actually 0d 0a (checked by a USBDynamixel).
Also, i am using a max485 chip to convert rx/tx data to rs485 standard.
NEVER
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Post by Bullit » Mon Nov 23, 2009 10:13 pm

Post by Bullit
Mon Nov 23, 2009 10:13 pm

What baud rate are you communicating at?
What baud rate are you communicating at?
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Post by NEVER » Mon Nov 23, 2009 11:40 pm

Post by NEVER
Mon Nov 23, 2009 11:40 pm

1 Mbps
1 Mbps
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Post by Bullit » Tue Nov 24, 2009 12:48 am

Post by Bullit
Tue Nov 24, 2009 12:48 am

gumstix built in serial ports do not resolve to 1Mbps, the closest I think is 921kbps but that is not close enough. I use gumstix for my robots but I use a USB ftdi module to get 1Mbps RS485.
gumstix built in serial ports do not resolve to 1Mbps, the closest I think is 921kbps but that is not close enough. I use gumstix for my robots but I use a USB ftdi module to get 1Mbps RS485.
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Post by NEVER » Tue Nov 24, 2009 12:54 pm

Post by NEVER
Tue Nov 24, 2009 12:54 pm

i even tried lesser bauds, but no difference. Packets without 0a work fine but wherever a 0a packet is sent, packet received at the other end becomes 0d 0a....
?????
i even tried lesser bauds, but no difference. Packets without 0a work fine but wherever a 0a packet is sent, packet received at the other end becomes 0d 0a....
?????
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Post by NEVER » Tue Nov 24, 2009 7:31 pm

Post by NEVER
Tue Nov 24, 2009 7:31 pm

I analyzed the signals from serial port of gumstix through Logic Analyzer (www.saleae.com) and calculated the baud to be 1Mbps, so serial port of gumstix is definitely reaching 1Mbps.
I analyzed the signals from serial port of gumstix through Logic Analyzer (www.saleae.com) and calculated the baud to be 1Mbps, so serial port of gumstix is definitely reaching 1Mbps.
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Post by Stephane » Wed Nov 25, 2009 12:27 am

Post by Stephane
Wed Nov 25, 2009 12:27 am

Hi,

0x0A turning into a 0x0D, 0x0A ... That sounds like a conversion from /n to /r/n.

Would you be sending data from a Windows machine?
If so check the options you open your COM port with. /n converted to /r/n is the typical things you have when you write into files in Microsoft OSes, and that is why the "b" exists in fopen( "file", "wb" ) when you want to write non-text data.

I hope this helps.

Stéphane
Hi,

0x0A turning into a 0x0D, 0x0A ... That sounds like a conversion from /n to /r/n.

Would you be sending data from a Windows machine?
If so check the options you open your COM port with. /n converted to /r/n is the typical things you have when you write into files in Microsoft OSes, and that is why the "b" exists in fopen( "file", "wb" ) when you want to write non-text data.

I hope this helps.

Stéphane
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