problem with an AX-12+

[elvisss]

Hello,
I have just bought an AX-12+, and I try to communicate with it by using an Atmega324.
Nevertheless, I don't know the ID of the servo, there is nothing written on it...
I tried to change the ID by sending a broadcast command, and after, switching on the LED of the new ID servo, but it didn't works...
I have checked that the command is the right one, because when I send it, in the same time, i check with the other USART the sent data.

When I switch on the servo, the led blinks once, and is red...the red color is ok, or does it mean there is a problem?...

Thank you for your answer, and sorry for my poor english...:-p

Elvisss

[Robo1]

You could try using the scan command to find the servo. Have you tried different baud setting. I think there 57600 out of the box and should be ID1. You could also try the 0xFE (I think) that's the universal address.

Bren

[elvisss]

Thank you for your help, I'm going to try it...
but I thought the default speed is 1mbps...or is it an other thing?...

[Robo1]

If you look through the manual these different speed setting. I only have DX-117 to go by, but most of them came with the same setting but one had a different speed and ID2 so took me some time to figure out why it wasn't working.

Bren

[elvisss]

Thank you,
I'm going to check it...
and what about the red led?...is it a normal color, or does it mean there is a problem?
It only blinks once, then stay switched off...

[hivemind]

I think the default baud might be 34 (0x22) ? - thats what it is for the DX-117. Also, the red light is standard.

[elvisss]

Hello,

I tried during 5 or 6 hours, but no results...
I would like to know if it is possible to use the 1 mbps at 8 MHz...maybe the problem comes from this point...

I also wanted to know something about AX-12 and RS485...
because I have a board on which I will plug my Atmega, and the board has a RS485 port...

But I am a newbie, so i am not sure if it is possible to send data from the board directly...

Thanks for the previous answers!!

[JonHylands]

Yes, you can use 1 Mbps from an 8 MHz ATmega. I do it all the time.

AX-12 has nothing to do with RS-485.

How do you have the bus connected to your ATmega?

- Jon

[elvisss]

Thank you for the tip!
But now, I understand nothing ...
I wrote several codes, and none is ok...I have now way to check the speed of the second USART, the one at 1 Mbps...
And when I try to use both USART, I have strange results...
I connected Rx and Tx pins of the second USART , and I try to desactivate the TX pin in order to be able to recieve data...but it doesn't work...
I never programmed Atmega before...with only one USART, it's ok, but with two, it's too difficult...
Does anybody has a good code for an Atmega 324?
I begin to think about buying an CM5 or USB2Dynamixel...

[JonHylands]

I sell a board that allows a PC to talk to the Bioloid bus directly over USB.

http://www.huvrobotics.com

I also have some code on my site that works as a bus device on an ATmega. See http://www.bioloid.info, under User Projects on the 6-axis IMU page.

- Jon

[elvisss]

your board seems very interesting!
But what about the software?...I run under linux...
I fact, I was thinking to buy a CM5 because it has a scan mode (only for this reason...) because I am not sure of the adresse and of the speed of my AX12...
is it possible to do so with your board?

[JonHylands]

Yes, my board gives you direct access to the bus. You can open the serial connection at any baud rate you like, and send out a series of pings to each allowable ID to see if you get a response (that's what I do).

It also works fine in Linux - the drivers for the FT232 were included back in around 2.4, so anything after that should be fine.

- Jon

[elvisss]

Thank you very much for your help!
I have an other question...is it possible to send data to an AX12 directly from a serial bus if the speed of the servomotor is, for instance, 9600 bps?...
I know this is not very fast, but i would like to make tests with only one motor, to know if i should buy more...

[JonHylands]

No, you can't. You can talk to it from a micro-controller, with some supporting hardware (or with none if you're using an ATmegaXXX), or you can use an interface board like I sell.

The problem is the serial bus is a one-wire bus - both Rx and Tx are on the same line.

- Jon

[elvisss]

yes, I know the protocol, since I triedd to send data to the AX12 with an Atmega...but If I don't care about the data sent by the motor (I know, it's stupid...), could it be possible?