hp and Karl Hammar, we already have sketch of control chain here: http://wiki.portalmod.com/wiki/Control_Chain
On 6 November 2014 10:56, <[email protected]> wrote: > Gianfranco (The MOD Team): > ... > > The physical interface of the Control Chain devices is an RS-485 > > full-duplex serial line running at 1Mbit/sec. Currently up to eight > > devices can be daisy chained and by use of the RJ-45 cable we also > > power the devices ( 1 pair for input,1 for output and 1 for power > supply). > ... > > How are you handling "collisions" and idle bus (rs485 does not > specify that kind of things) ? > > Idle bus can be taken care of with a resistor devider (as described > in e.g. [1]), but that solution draws power when the bus is idle. > Why not a "active" kind of termination by connecting "A" to +2, 3.3, > or 5V and "B" to GND (or vice versa), both throught 60 Ohm resistors ? > > "Collision" handling can be avoided by using a one master and letting > the other nodes to be slaves, and polling the slaves. > Or one can use something similar to J1708 [2] and CAN by driving the > device enable pin instead of the transmit pin and let the bus "float" > (by setting the output driver to hi-z) up/down to the "recessive" state > by a "idle bus"/failstate circuit. You have to have some software to > detect any collisions then. > > I drafted some thoughts in [3], but havn't implemented it "yet". > > Ideas ? > > Regards, > /Karl Hammar > > [1] http://www.ti.com/lit/an/slyt324/slyt324.pdf > [2] http://www.ti.com/lit/an/snla038b/snla038b.pdf > [3] http://turkos.aspodata.se/git/openhw/serial_bus/Readme > > ----------------------------------------------------------------------- > Aspö Data > Lilla Aspö 148 > S-742 94 Östhammar > Sweden > +46 173 140 57 > > > _______________________________________________ > Linux-audio-dev mailing list > [email protected] > http://lists.linuxaudio.org/listinfo/linux-audio-dev >
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