So, I'm going to fiddle around with a handful of ECE306 project boards, however, I'm looking to network about ten of them together.

I didn't know if anybody has experience with this, or if it is even possible. I know it has the RS-232 port built in, and you can butcher the protocol some so that it only requires data / ground.

Is the best bet to do a "network" is to do the two wire communication and home brew a token ring network, with one board being the controller and the others being nodes waiting to be pulsed on their information? The nodes won't talk to each other; they will only talk to the main controller.

5/15/2008 10:51:00 AM

Anybody?

5/20/2008 10:24:17 AM

you only need 3 wires for RS 232. The rest are handshaking protocalls.

the root basic communications just needs "no parity" whatever baudrate and hardware control.

make sure you use null connectors where needed.

I've done a LOT of RS232 but it's all been in Labview which handles most everything for you.

[Edited on May 20, 2008 at 3:40 PM. Reason : honestly I can't remember if hardware control is right or not... ]

5/20/2008 3:40:05 PM

Can't you sneak by with just two wires, ground and data (being SND and RCV) tied to the same line?

Basically all the nodes will be "listening" for their "code" to be transmitted along the data line.
Upon receiving their unique "code" they will reply with whatever relevant information is requested.
The master will be the only one that can transmit without first receiving a request, this is to prevent an collisions along the single data line. (Wheel and spoke network)

5/22/2008 3:53:55 PM

I don't know how the 306 boards are setup but to do what your talking about would require a bus controller on wired OR logic... both are things you typically want to avoid.

Sounds like your trying to implement something along the lines of I2C... which uses just 2 wires, but somewhere along the way the hardware itself has to be able to physically transmit and physically receive the signal... These are vastly different circuits. Ones made to receive a wide range of signals the other is made to drive a specified load... IE you would need a physical switch between the RX/TX portions on the board to do the TDM part. RS232 is setup to be full duplex.

I mean, it IS probably possible to do what your talking about doing, but your talking about using software to do the bus controller. Software is much much much slower than hardware so it's a pretty bad idea if you wanted to achieve any reasonable speed. however if your just sending something like GPIB commands then yeah that would work reasonable.

[Edited on May 22, 2008 at 7:52 PM. Reason : it's possible to do what your talking about... but bad practice to do in software]

5/22/2008 7:47:03 PM

Quote :

"I mean, it IS probably possible to do what your talking about doing, but your talking about using software to do the bus controller. Software is much much much slower than hardware so it's a pretty bad idea if you wanted to achieve any reasonable speed. however if your just sending something like GPIB commands then yeah that would work reasonable. "

The Renesas boards they're using aren't that fast to begin with. I'm guessing pureetofu is just doing this for shits and giggles, in which case, the speed isn't too critical for him.

But, it sounds like he's going to rig his own protocol using the RS232 controllers built in on the boards, which should do what he's trying to do.

5/22/2008 11:18:19 PM

goFigure I'm not doing anything that requires speed, just building a fun little project for around the house.

Once (if) I get these boards in from Motorolla i'll report back.

5/26/2008 9:29:50 AM