Joined: 11 Oct 2004 Posts: 1791 Location: London, UK
Posted: Thu Sep 20, 2007 8:38 pm Post subject:
Jon,
Arduino doesnt have the circuitry to buffer between the RX and TX.
Do you think that simply shorting its RX and TX onto the AX12 data line would allow the Arduino to communicate with the AX12 (given appropriate code that would disable RX when TX is talking and v.v.) ?
Joined: 09 Nov 2006 Posts: 512 Location: Ontario, Canada
Posted: Thu Sep 20, 2007 10:07 pm Post subject:
Yes, that's what all my device boards do...
The ATmega UART can selectively switch off the transmit and receive pins while it is operating, which is what the code my brother wrote does. In general, the Tx pin is disabled, and its in receive mode. When it needs to transmit an answer back again, it disables the Rx pin, enables the Tx, and then sends the response, and switches them back again.
Joined: 11 Oct 2004 Posts: 1791 Location: London, UK
Posted: Fri Sep 21, 2007 7:36 am Post subject:
i didn't know that you had modules working this way. This issue was discussed before here with relation to the Pepper board and somehow I got the impression that there was some kind of electrical or signal problem with shorting the RX and TX on the Atmega.
But this is great news because it means that basically any Atmega controller board (with the 1mbps UART) can control the Bioloid bus.
Joined: 09 Nov 2006 Posts: 512 Location: Ontario, Canada
Posted: Fri Sep 21, 2007 2:07 pm Post subject:
You need to cross the Rx and Tx pins of the ATmega168, and use the software I pointed out to you in my first reply. Don't short the pins until you have the software loaded, because otherwise you can burn out the UART. I typically solder a molex 2-pin header to the two pins, and then put a jumper across (see pic below - the jumper is just above the bus connection)...
Then you can modify that software so that instead of representing an IMU, it simulated an AX-12. The control table for the AX-12 is very well defined, and it should be fairly simple to do most of it. It really depends on how deep you want your simulation to be...
sorry for asking question where by alot of people asked before.i bought arduino months ago and wish to use its IDE to control ax-12.i saw a few thread but i just confuse with a few methods for connecting the rx and tx pins into ttl half dupex.hope you guys can give me some guidance
sorry for asking question where by alot of people asked before.i bought arduino months ago and wish to use its IDE to control ax-12.i saw a few thread but i just confuse with a few methods for connecting the rx and tx pins into ttl half dupex.hope you guys can give me some guidance
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