is there serial access

[timpart]

[TrikingSheep]

I think Andrew's idea was to connect the RPi's data port to a 4 way or 8 way switch matrix and use the RPi's GPIO buss to switch the switch.

This could be done all with logic chips.

To switch 4 ways would need 2 GPIO lines and 8 way would need 3 GPIO lines.



Using standard GPIO lines as UARTS is possible, but you would need to write the "bit banging" and UART code to be able to do this, something I had to do for my VHDL course I did when doing my MSc.




Kind Regards,



Julian.

[timpart]

[mhonman]

A quick way of getting a couple of extra UARTs would be something like an ARM microcontroller board (e.g. the microcontrollers on ST's "discovery" boards have 3 or 4 UARTs).

But most likely the easiest way is to have multiple USB RSR232 converters on a hub connected to the RPi or other master machine. In that case I'd be tempted to go for a Vista licensed ultra SFF PC (e.g. Lenovo M58p) which having a gigabit NIC could also be a storage server for the cluster. And for that matter it'd probably be able to supply enough 5V for 8x Parallella boards, into the bargain.

[TrikingSheep]

The down side of using USB / RS232 converters is that they output RS232 levels +/- 12V.

The Parallella's only use LVTTL levels of 0V to 3.3V.

For the USB / RS232 converters to work there would have to be MAX3232, or similar, converter ICs at each Parallella to convert back to LVTTL.


Kind Regards,


Julian.

[TrikingSheep]

[mhonman]

[TrikingSheep]

[9600]

[shodruk]

Thanks everyone!
I'll be careful not to connect to the wrong pins.