short TX & RX

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4 postsPage 1 of 1

short TX & RX

Post by JavaRN » Sun Jul 12, 2009 4:07 pm

Post by JavaRN
Sun Jul 12, 2009 4:07 pm

For communication with ax-12 using com 3 it is necessary to short TX & RX, which is the best way to do so through connecting wires or soldeting tx and rx together?

Thanks
For communication with ax-12 using com 3 it is necessary to short TX & RX, which is the best way to do so through connecting wires or soldeting tx and rx together?

Thanks
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Post by StuartL » Mon Jul 13, 2009 8:52 am

Post by StuartL
Mon Jul 13, 2009 8:52 am

Shorting them is absolutely fine on the condition that you ensure that the TX line is tri-stated when you're not transmitting. It's probably also worth putting a series resistor on the bus so that if someone else does transmit at the same time you don't blow one of the transmitters up.

If you were to put the series resistor between the TX and RX and then connect the RX to the bus you could even deliberately receive your own transmissions and see if they're different to your intended transmission. The 'collision' would cause packet corruption and with clever (but well documented) algorithms you can retry the transmission.
Shorting them is absolutely fine on the condition that you ensure that the TX line is tri-stated when you're not transmitting. It's probably also worth putting a series resistor on the bus so that if someone else does transmit at the same time you don't blow one of the transmitters up.

If you were to put the series resistor between the TX and RX and then connect the RX to the bus you could even deliberately receive your own transmissions and see if they're different to your intended transmission. The 'collision' would cause packet corruption and with clever (but well documented) algorithms you can retry the transmission.
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Post by roboard » Mon Jul 13, 2009 12:01 pm

Post by roboard
Mon Jul 13, 2009 12:01 pm

see the reference connection

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see the reference connection

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Post by PedroR » Mon Jul 13, 2009 1:08 pm

Post by PedroR
Mon Jul 13, 2009 1:08 pm

Hey

Just a quick explanation on the pics above:

The pic on the bottom shows the connector that ships with roboard. It is the connector for COMM3 and it comes with 4 wires: two for power and two for RX and TX. What they short there is RX and TX and the connect them all - GND, Vdd and DATA (which is RX+TX) - to the Bioloid connector.

I had never seen the connector they use in the 2nd and 3rd pics but it looks like a standard connector.

Another solution is getting a Bioloid cable, cutting the connectors on one end and soldering the wires from the Bioloid Cable directly to the wires of the Roboard connector (the one on the pic at the bottom).
This way you get a cable that connects directly onto the servo socket.

You'll probably want to make it a Y cable with 2 or 3 Servo connectors for added flexibility.

Regards
Pedro.
Hey

Just a quick explanation on the pics above:

The pic on the bottom shows the connector that ships with roboard. It is the connector for COMM3 and it comes with 4 wires: two for power and two for RX and TX. What they short there is RX and TX and the connect them all - GND, Vdd and DATA (which is RX+TX) - to the Bioloid connector.

I had never seen the connector they use in the 2nd and 3rd pics but it looks like a standard connector.

Another solution is getting a Bioloid cable, cutting the connectors on one end and soldering the wires from the Bioloid Cable directly to the wires of the Roboard connector (the one on the pic at the bottom).
This way you get a cable that connects directly onto the servo socket.

You'll probably want to make it a Y cable with 2 or 3 Servo connectors for added flexibility.

Regards
Pedro.
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