I2C connection?
I2C connection?
by siempre.aprendiendo
Mon Mar 10, 2008 2:46 pm
Would it be possible (and easy) to create a I2C module to the AX12+ bus (as the greats havimo camera or Jon's board) to connect and use I2C sensors?
by JonHylands
Mon Mar 10, 2008 3:48 pm
Well, its possible, but it would be hard to do a generic I2C interface, for the same reason its hard to do a generic serial interface.
I2C is a command-based protocol, and Bioloid devices use a data-based system (the control table). For a specific I2C sensor (like say a sonar or LCD panel) it would be easy to do that, because then you can handle the commands in the micro-controller you're using to interface to the bus, and still end up with a control table representation of the data.
- Jon
I2C is a command-based protocol, and Bioloid devices use a data-based system (the control table). For a specific I2C sensor (like say a sonar or LCD panel) it would be easy to do that, because then you can handle the commands in the micro-controller you're using to interface to the bus, and still end up with a control table representation of the data.
- Jon
by siempre.aprendiendo
Tue Mar 11, 2008 12:41 pm
JonHylands wrote:Well, its possible, but it would be hard to do a generic I2C interface, for the same reason its hard to do a generic serial interface.
I2C is a command-based protocol, and Bioloid devices use a data-based system (the control table). For a specific I2C sensor (like say a sonar or LCD panel) it would be easy to do that, because then you can handle the commands in the micro-controller you're using to interface to the bus, and still end up with a control table representation of the data.
- Jon
I'm not very used to I2C... what are the "differences" between I2C "implementations" ?
Thanks!
by JonHylands
Tue Mar 11, 2008 1:48 pm
There really isn't any. I2C is a serial communications protocol, like RS-232 or SPI or even USB. Its just a specification that allows two or more devices to communicate using a couple wires.
In order to support putting an I2C port (or even a regular serial port) on say my I/O board, we would need to add a few new commands to the bioloid bus specification (current it has commands like WRITE_DATA and READ_DATA). We would need to add something like SEND_COMMAND, which (from a philosophical standpoint) goes against what Robotis tried to do with the control-table implementation. When I build a Bioloid bus device, it is important to me that it works exactly the same as Robotis devices, including having a similar layout to the control table, and a similar way to talk to the device.
- Jon
In order to support putting an I2C port (or even a regular serial port) on say my I/O board, we would need to add a few new commands to the bioloid bus specification (current it has commands like WRITE_DATA and READ_DATA). We would need to add something like SEND_COMMAND, which (from a philosophical standpoint) goes against what Robotis tried to do with the control-table implementation. When I build a Bioloid bus device, it is important to me that it works exactly the same as Robotis devices, including having a similar layout to the control table, and a similar way to talk to the device.
- Jon
Thank you very much, Jon
by Pev
Wed Mar 12, 2008 9:20 am
JonHylands wrote:There really isn't any. I2C is a serial communications protocol, like RS-232 or SPI or even USB. Its just a specification that allows two or more devices to communicate using a couple wires.
In order to support putting an I2C port (or even a regular serial port) on say my I/O board, we would need to add a few new commands to the bioloid bus specification (current it has commands like WRITE_DATA and READ_DATA). We would need to add something like SEND_COMMAND, which (from a philosophical standpoint) goes against what Robotis tried to do with the control-table implementation. When I build a Bioloid bus device, it is important to me that it works exactly the same as Robotis devices, including having a similar layout to the control table, and a similar way to talk to the device.
- Jon
I did a very basic I2C using the pepperm i/o board - used a register to act as a trigger to send an I2C command to a sensor then loaded the result back into another register and read it from there. The tough bit is the timing as the sensor took 65ms to respond, so it was trigger it - do a load of other stuff then read the results. I have considered putting an I2C slave processor with the module and having that service all the I2C sensors continually from powerup then just using the I/O module to read the I2C slave when requested with the results for each sensor at different register addresses but have never got around to implementing it.
Pev
